@nameuse with value relax in conditionals

1

This is a follow-up to this question: @nameuse as conditional where i asked about how to use expandafter if i combine @nameuse with ifx. However, in my real-life example, i use relax as a default value for dynamically assigned csnames. I want to know if these control sequences have a specific value, or if they are default. My naive approach would be something like:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

but this doesn't work. In its simplest form it gives "false", but in more complex form (with xmltex, a macro definition, and another ifx-structure around) i get Extra else errors. I'd like to understand why that is and what i need to do to make it work.

Bonus: I'd prefer a “plain” solution, i.e. no expl3-syntax or complex packages since i want to be as independent as possible from my code's user's configurations.

EDIT:

Here is the problem i'm facing: I want to store some information of the cells of a table. I'm using David Carlisle's xmltex mechanism to parse html tables. Elements are grabbed and transmitted directly into corresponding tex macros. The necessary counters are incremented at the beginning of every such macro.

In the cell definiton iterate over all cells and use a global macro

gdefSetCellProp#1#2{expandafterdefcsname cell-thecurtab-thecurrow-thecurcel-#2endcsname{#1}}

to store properties like the cells calculated width (content in mybox; @tempdima=wdmybox), its content, and its background-color. E.g., i am in the second table, third row, second column, then the width of that cell (e.g. "12mm") is stored with SetCellProp{12mm}{width} which "creates" a control sequence named cell-3-2-2-width that yields the value "12mm".

Likewise, i have want to store the biggest value for width so far using

gdefSetColProp#1#2{expandafterdefcsname col-thecurtab-thecurcel-#2endcsname{#1}}

The macro that returns that value is defined as

gdefGetCurColProp#1{csname cell-thecurtab-thecurcel-#1endcsname}

Note, that this definition doesn't care about the row i am in. Since i re-count cells each row, i need to decide whether to overwrite the maximum value, or not if it is present at all.

To do so, in each cell, we need to check if

• 
  
  1. a maxwidth for the column the current cell is in, is already given
  
  


• 2a. if no, make the current cell's width maxwidth for the whole column


• 2b. if yes, look if the value for the current width is larger than maxwidth for the column


• 3a if yes, make that current value the new maxwidth for the while column,


• 3b if no, leave everything as it is.

The part of my cell definition so far looks like:

  %% check if maxwidth for the col is already given:

  ifxcsname cell-thecurtab-thecurcel-maxidthendcsnamerelax

    %% if no, take current width (@tempdima) as maxwidth

    expandafterSetColPropexpandafter{the@tempdima}{maxwidth}%

  else

    %% else check if current width is larger than  maxwidth:

    expandafter@tempdimbGetCurColProp{maxwidth}% 

    ifdim@tempdimb<@tempdima

      %% if so, reassign maxwidth with curwidth:

      expandafterSetColPropexpandafter{the@tempdima}{maxwidth}%

    fi

  fi

where curtab counts the tables, currow counts the current row, and curcel the number of the cell in the row (gets reset to 1 at the beginning of every row). The aim is to get the maximum width of any column my table has.

I hope that explains my problem a little bit.

tex-core conditionals

share|improve this question

edited Jan 24 at 14:06

Lupino

asked Jan 24 at 12:13

LupinoLupino

1,176610

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  > blafasel=macro://->relax .//l.9 showblafasel and relax=relax.//l.10 showrelax show that relax and blafasel are different for ifx. One is a macro expanding to relax, the other one is relax.
  
  – moewe
  Jan 24 at 12:17
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try expandafterexpandafterexpandafterifx@nameuse{blafasel}testrelax where testrelax is deftestrelax{relax}. Or expandafterexpandafterexpandafterexpandafterexpandafterexpandafterexpandafterifx@nameuse{blafasel}relax to test not blafasel against relax, but the expansion of blafasel.
  
  – moewe
  Jan 24 at 12:18
  
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Copying my comment from the other post: ifx compares the meaning of two tokens without expanding them previously, so relax is valid. Of course the comparison will only be true if both tokens expand to relax, for instance this code first yields foo is NOT relax because, obviously, foo is not relax, it only contains relax in its definition. The second comparison yields foo is relax because you make foo an exact copy of relax.
  
  – Phelype Oleinik
  Jan 24 at 12:22
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Note that undefined csnames are relax by default, so if you had not initialised blafasel with @namedef{blafasel}{relax} then expandafterexpandafterexpandafterifx@nameuse{blafasel}relax would have worked.
  
  – moewe
  Jan 24 at 12:23
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @moewe the whole point of this exersice is to test whether my cs is initialised, or not. If not, then my next step is to initialise it with a pre-defined default value (other than relax).
  
  – Lupino
  Jan 24 at 12:28
  

  
  
  
  

 | 
show 2 more comments

1

This is a follow-up to this question: @nameuse as conditional where i asked about how to use expandafter if i combine @nameuse with ifx. However, in my real-life example, i use relax as a default value for dynamically assigned csnames. I want to know if these control sequences have a specific value, or if they are default. My naive approach would be something like:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

but this doesn't work. In its simplest form it gives "false", but in more complex form (with xmltex, a macro definition, and another ifx-structure around) i get Extra else errors. I'd like to understand why that is and what i need to do to make it work.

Bonus: I'd prefer a “plain” solution, i.e. no expl3-syntax or complex packages since i want to be as independent as possible from my code's user's configurations.

EDIT:

Here is the problem i'm facing: I want to store some information of the cells of a table. I'm using David Carlisle's xmltex mechanism to parse html tables. Elements are grabbed and transmitted directly into corresponding tex macros. The necessary counters are incremented at the beginning of every such macro.

In the cell definiton iterate over all cells and use a global macro

gdefSetCellProp#1#2{expandafterdefcsname cell-thecurtab-thecurrow-thecurcel-#2endcsname{#1}}

to store properties like the cells calculated width (content in mybox; @tempdima=wdmybox), its content, and its background-color. E.g., i am in the second table, third row, second column, then the width of that cell (e.g. "12mm") is stored with SetCellProp{12mm}{width} which "creates" a control sequence named cell-3-2-2-width that yields the value "12mm".

Likewise, i have want to store the biggest value for width so far using

gdefSetColProp#1#2{expandafterdefcsname col-thecurtab-thecurcel-#2endcsname{#1}}

The macro that returns that value is defined as

gdefGetCurColProp#1{csname cell-thecurtab-thecurcel-#1endcsname}

Note, that this definition doesn't care about the row i am in. Since i re-count cells each row, i need to decide whether to overwrite the maximum value, or not if it is present at all.

To do so, in each cell, we need to check if

• 
  
  1. a maxwidth for the column the current cell is in, is already given
  
  


• 2a. if no, make the current cell's width maxwidth for the whole column


• 2b. if yes, look if the value for the current width is larger than maxwidth for the column


• 3a if yes, make that current value the new maxwidth for the while column,


• 3b if no, leave everything as it is.

The part of my cell definition so far looks like:

  %% check if maxwidth for the col is already given:

  ifxcsname cell-thecurtab-thecurcel-maxidthendcsnamerelax

    %% if no, take current width (@tempdima) as maxwidth

    expandafterSetColPropexpandafter{the@tempdima}{maxwidth}%

  else

    %% else check if current width is larger than  maxwidth:

    expandafter@tempdimbGetCurColProp{maxwidth}% 

    ifdim@tempdimb<@tempdima

      %% if so, reassign maxwidth with curwidth:

      expandafterSetColPropexpandafter{the@tempdima}{maxwidth}%

    fi

  fi

where curtab counts the tables, currow counts the current row, and curcel the number of the cell in the row (gets reset to 1 at the beginning of every row). The aim is to get the maximum width of any column my table has.

I hope that explains my problem a little bit.

tex-core conditionals

share|improve this question

edited Jan 24 at 14:06

Lupino

asked Jan 24 at 12:13

LupinoLupino

1,176610

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  > blafasel=macro://->relax .//l.9 showblafasel and relax=relax.//l.10 showrelax show that relax and blafasel are different for ifx. One is a macro expanding to relax, the other one is relax.
  
  – moewe
  Jan 24 at 12:17
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try expandafterexpandafterexpandafterifx@nameuse{blafasel}testrelax where testrelax is deftestrelax{relax}. Or expandafterexpandafterexpandafterexpandafterexpandafterexpandafterexpandafterifx@nameuse{blafasel}relax to test not blafasel against relax, but the expansion of blafasel.
  
  – moewe
  Jan 24 at 12:18
  
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Copying my comment from the other post: ifx compares the meaning of two tokens without expanding them previously, so relax is valid. Of course the comparison will only be true if both tokens expand to relax, for instance this code first yields foo is NOT relax because, obviously, foo is not relax, it only contains relax in its definition. The second comparison yields foo is relax because you make foo an exact copy of relax.
  
  – Phelype Oleinik
  Jan 24 at 12:22
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Note that undefined csnames are relax by default, so if you had not initialised blafasel with @namedef{blafasel}{relax} then expandafterexpandafterexpandafterifx@nameuse{blafasel}relax would have worked.
  
  – moewe
  Jan 24 at 12:23
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @moewe the whole point of this exersice is to test whether my cs is initialised, or not. If not, then my next step is to initialise it with a pre-defined default value (other than relax).
  
  – Lupino
  Jan 24 at 12:28
  

  
  
  
  

 | 
show 2 more comments

1

1

1

This is a follow-up to this question: @nameuse as conditional where i asked about how to use expandafter if i combine @nameuse with ifx. However, in my real-life example, i use relax as a default value for dynamically assigned csnames. I want to know if these control sequences have a specific value, or if they are default. My naive approach would be something like:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

but this doesn't work. In its simplest form it gives "false", but in more complex form (with xmltex, a macro definition, and another ifx-structure around) i get Extra else errors. I'd like to understand why that is and what i need to do to make it work.

Bonus: I'd prefer a “plain” solution, i.e. no expl3-syntax or complex packages since i want to be as independent as possible from my code's user's configurations.

EDIT:

Here is the problem i'm facing: I want to store some information of the cells of a table. I'm using David Carlisle's xmltex mechanism to parse html tables. Elements are grabbed and transmitted directly into corresponding tex macros. The necessary counters are incremented at the beginning of every such macro.

In the cell definiton iterate over all cells and use a global macro

gdefSetCellProp#1#2{expandafterdefcsname cell-thecurtab-thecurrow-thecurcel-#2endcsname{#1}}

to store properties like the cells calculated width (content in mybox; @tempdima=wdmybox), its content, and its background-color. E.g., i am in the second table, third row, second column, then the width of that cell (e.g. "12mm") is stored with SetCellProp{12mm}{width} which "creates" a control sequence named cell-3-2-2-width that yields the value "12mm".

Likewise, i have want to store the biggest value for width so far using

gdefSetColProp#1#2{expandafterdefcsname col-thecurtab-thecurcel-#2endcsname{#1}}

The macro that returns that value is defined as

gdefGetCurColProp#1{csname cell-thecurtab-thecurcel-#1endcsname}

Note, that this definition doesn't care about the row i am in. Since i re-count cells each row, i need to decide whether to overwrite the maximum value, or not if it is present at all.

To do so, in each cell, we need to check if

• 
  
  1. a maxwidth for the column the current cell is in, is already given
  
  


• 2a. if no, make the current cell's width maxwidth for the whole column


• 2b. if yes, look if the value for the current width is larger than maxwidth for the column


• 3a if yes, make that current value the new maxwidth for the while column,


• 3b if no, leave everything as it is.

The part of my cell definition so far looks like:

  %% check if maxwidth for the col is already given:

  ifxcsname cell-thecurtab-thecurcel-maxidthendcsnamerelax

    %% if no, take current width (@tempdima) as maxwidth

    expandafterSetColPropexpandafter{the@tempdima}{maxwidth}%

  else

    %% else check if current width is larger than  maxwidth:

    expandafter@tempdimbGetCurColProp{maxwidth}% 

    ifdim@tempdimb<@tempdima

      %% if so, reassign maxwidth with curwidth:

      expandafterSetColPropexpandafter{the@tempdima}{maxwidth}%

    fi

  fi

where curtab counts the tables, currow counts the current row, and curcel the number of the cell in the row (gets reset to 1 at the beginning of every row). The aim is to get the maximum width of any column my table has.

I hope that explains my problem a little bit.

tex-core conditionals

share|improve this question

edited Jan 24 at 14:06

Lupino

asked Jan 24 at 12:13

LupinoLupino

1,176610

This is a follow-up to this question: @nameuse as conditional where i asked about how to use expandafter if i combine @nameuse with ifx. However, in my real-life example, i use relax as a default value for dynamically assigned csnames. I want to know if these control sequences have a specific value, or if they are default. My naive approach would be something like:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

but this doesn't work. In its simplest form it gives "false", but in more complex form (with xmltex, a macro definition, and another ifx-structure around) i get Extra else errors. I'd like to understand why that is and what i need to do to make it work.

Bonus: I'd prefer a “plain” solution, i.e. no expl3-syntax or complex packages since i want to be as independent as possible from my code's user's configurations.

EDIT:

Here is the problem i'm facing: I want to store some information of the cells of a table. I'm using David Carlisle's xmltex mechanism to parse html tables. Elements are grabbed and transmitted directly into corresponding tex macros. The necessary counters are incremented at the beginning of every such macro.

In the cell definiton iterate over all cells and use a global macro

gdefSetCellProp#1#2{expandafterdefcsname cell-thecurtab-thecurrow-thecurcel-#2endcsname{#1}}

to store properties like the cells calculated width (content in mybox; @tempdima=wdmybox), its content, and its background-color. E.g., i am in the second table, third row, second column, then the width of that cell (e.g. "12mm") is stored with SetCellProp{12mm}{width} which "creates" a control sequence named cell-3-2-2-width that yields the value "12mm".

Likewise, i have want to store the biggest value for width so far using

gdefSetColProp#1#2{expandafterdefcsname col-thecurtab-thecurcel-#2endcsname{#1}}

The macro that returns that value is defined as

gdefGetCurColProp#1{csname cell-thecurtab-thecurcel-#1endcsname}

Note, that this definition doesn't care about the row i am in. Since i re-count cells each row, i need to decide whether to overwrite the maximum value, or not if it is present at all.

To do so, in each cell, we need to check if

• 
  
  1. a maxwidth for the column the current cell is in, is already given
  
  


• 2a. if no, make the current cell's width maxwidth for the whole column


• 2b. if yes, look if the value for the current width is larger than maxwidth for the column


• 3a if yes, make that current value the new maxwidth for the while column,


• 3b if no, leave everything as it is.

The part of my cell definition so far looks like:

  %% check if maxwidth for the col is already given:

  ifxcsname cell-thecurtab-thecurcel-maxidthendcsnamerelax

    %% if no, take current width (@tempdima) as maxwidth

    expandafterSetColPropexpandafter{the@tempdima}{maxwidth}%

  else

    %% else check if current width is larger than  maxwidth:

    expandafter@tempdimbGetCurColProp{maxwidth}% 

    ifdim@tempdimb<@tempdima

      %% if so, reassign maxwidth with curwidth:

      expandafterSetColPropexpandafter{the@tempdima}{maxwidth}%

    fi

  fi

where curtab counts the tables, currow counts the current row, and curcel the number of the cell in the row (gets reset to 1 at the beginning of every row). The aim is to get the maximum width of any column my table has.

I hope that explains my problem a little bit.

tex-core conditionals

tex-core conditionals

share|improve this question

edited Jan 24 at 14:06

Lupino

asked Jan 24 at 12:13

LupinoLupino

1,176610

share|improve this question

edited Jan 24 at 14:06

Lupino

asked Jan 24 at 12:13

LupinoLupino

1,176610

share|improve this question

share|improve this question

edited Jan 24 at 14:06

Lupino

edited Jan 24 at 14:06

Lupino

edited Jan 24 at 14:06

Lupino

asked Jan 24 at 12:13

LupinoLupino

1,176610

asked Jan 24 at 12:13

LupinoLupino

1,176610

asked Jan 24 at 12:13

LupinoLupino

1,176610

1,176610

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  > blafasel=macro://->relax .//l.9 showblafasel and relax=relax.//l.10 showrelax show that relax and blafasel are different for ifx. One is a macro expanding to relax, the other one is relax.
  
  – moewe
  Jan 24 at 12:17
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try expandafterexpandafterexpandafterifx@nameuse{blafasel}testrelax where testrelax is deftestrelax{relax}. Or expandafterexpandafterexpandafterexpandafterexpandafterexpandafterexpandafterifx@nameuse{blafasel}relax to test not blafasel against relax, but the expansion of blafasel.
  
  – moewe
  Jan 24 at 12:18
  
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Copying my comment from the other post: ifx compares the meaning of two tokens without expanding them previously, so relax is valid. Of course the comparison will only be true if both tokens expand to relax, for instance this code first yields foo is NOT relax because, obviously, foo is not relax, it only contains relax in its definition. The second comparison yields foo is relax because you make foo an exact copy of relax.
  
  – Phelype Oleinik
  Jan 24 at 12:22
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Note that undefined csnames are relax by default, so if you had not initialised blafasel with @namedef{blafasel}{relax} then expandafterexpandafterexpandafterifx@nameuse{blafasel}relax would have worked.
  
  – moewe
  Jan 24 at 12:23
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @moewe the whole point of this exersice is to test whether my cs is initialised, or not. If not, then my next step is to initialise it with a pre-defined default value (other than relax).
  
  – Lupino
  Jan 24 at 12:28
  

  
  
  
  

 | 
show 2 more comments

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  > blafasel=macro://->relax .//l.9 showblafasel and relax=relax.//l.10 showrelax show that relax and blafasel are different for ifx. One is a macro expanding to relax, the other one is relax.
  
  – moewe
  Jan 24 at 12:17
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Try expandafterexpandafterexpandafterifx@nameuse{blafasel}testrelax where testrelax is deftestrelax{relax}. Or expandafterexpandafterexpandafterexpandafterexpandafterexpandafterexpandafterifx@nameuse{blafasel}relax to test not blafasel against relax, but the expansion of blafasel.
  
  – moewe
  Jan 24 at 12:18
  
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Copying my comment from the other post: ifx compares the meaning of two tokens without expanding them previously, so relax is valid. Of course the comparison will only be true if both tokens expand to relax, for instance this code first yields foo is NOT relax because, obviously, foo is not relax, it only contains relax in its definition. The second comparison yields foo is relax because you make foo an exact copy of relax.
  
  – Phelype Oleinik
  Jan 24 at 12:22
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Note that undefined csnames are relax by default, so if you had not initialised blafasel with @namedef{blafasel}{relax} then expandafterexpandafterexpandafterifx@nameuse{blafasel}relax would have worked.
  
  – moewe
  Jan 24 at 12:23
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @moewe the whole point of this exersice is to test whether my cs is initialised, or not. If not, then my next step is to initialise it with a pre-defined default value (other than relax).
  
  – Lupino
  Jan 24 at 12:28
  

  
  
  
  

> blafasel=macro://->relax .//l.9 showblafasel and relax=relax.//l.10 showrelax show that relax and blafasel are different for ifx. One is a macro expanding to relax, the other one is relax.

– moewe
Jan 24 at 12:17

> blafasel=macro://->relax .//l.9 showblafasel and relax=relax.//l.10 showrelax show that relax and blafasel are different for ifx. One is a macro expanding to relax, the other one is relax.

– moewe
Jan 24 at 12:17

Try expandafterexpandafterexpandafterifx@nameuse{blafasel}testrelax where testrelax is deftestrelax{relax}. Or expandafterexpandafterexpandafterexpandafterexpandafterexpandafterexpandafterifx@nameuse{blafasel}relax to test not blafasel against relax, but the expansion of blafasel.

– moewe
Jan 24 at 12:18

Try expandafterexpandafterexpandafterifx@nameuse{blafasel}testrelax where testrelax is deftestrelax{relax}. Or expandafterexpandafterexpandafterexpandafterexpandafterexpandafterexpandafterifx@nameuse{blafasel}relax to test not blafasel against relax, but the expansion of blafasel.

– moewe
Jan 24 at 12:18

1

1

Copying my comment from the other post: ifx compares the meaning of two tokens without expanding them previously, so relax is valid. Of course the comparison will only be true if both tokens expand to relax, for instance this code first yields foo is NOT relax because, obviously, foo is not relax, it only contains relax in its definition. The second comparison yields foo is relax because you make foo an exact copy of relax.

– Phelype Oleinik
Jan 24 at 12:22

Copying my comment from the other post: ifx compares the meaning of two tokens without expanding them previously, so relax is valid. Of course the comparison will only be true if both tokens expand to relax, for instance this code first yields foo is NOT relax because, obviously, foo is not relax, it only contains relax in its definition. The second comparison yields foo is relax because you make foo an exact copy of relax.

– Phelype Oleinik
Jan 24 at 12:22

Note that undefined csnames are relax by default, so if you had not initialised blafasel with @namedef{blafasel}{relax} then expandafterexpandafterexpandafterifx@nameuse{blafasel}relax would have worked.

– moewe
Jan 24 at 12:23

Note that undefined csnames are relax by default, so if you had not initialised blafasel with @namedef{blafasel}{relax} then expandafterexpandafterexpandafterifx@nameuse{blafasel}relax would have worked.

– moewe
Jan 24 at 12:23

@moewe the whole point of this exersice is to test whether my cs is initialised, or not. If not, then my next step is to initialise it with a pre-defined default value (other than relax).

– Lupino
Jan 24 at 12:28

@moewe the whole point of this exersice is to test whether my cs is initialised, or not. If not, then my next step is to initialise it with a pre-defined default value (other than relax).

– Lupino
Jan 24 at 12:28

 | 
show 2 more comments

3 Answers
3

active

oldest

votes

4

The problem you will confront will be that, unless you know in advance the types of arguments that may be passed to this test, they each may require differing numbers of expansions to finally reach the relax or not-relax condition.

Perhaps you need to fully expand your argument for the test:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

edeftmp{@nameuse{blafasel}}% MUST, HOWEVER, BE FULLY EXPANDABLE

expandafterifxtmprelax

   true

else

   false

fi



end{document}

Of course, this approach only works if the test argument is fully expandable.

---

Alternately, if it will always be a @nameuse that is part of the test, then the use of 3xexpandafter only produces 2 expansions. You need 7xexpandafter to get 3 expansions, resulting in a true test.

Rule: to get n expansions, you need 2^n - 1 instances of expandafter.

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterexpandafterexpandafter%

  expandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

share|improve this answer

edited Jan 24 at 16:42

answered Jan 24 at 12:18

Steven B. SegletesSteven B. Segletes

158k9204411

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks. I fear, i dont understand "fully expandable". my actual exampe is @namedef{blafaselc@mycounter}. The "value" of blasasel<x> can be a string, a dimension, a length, a number, a cs, or relax... Say, i know that blafasel1 is a string (or relax), blafasel2 is a dimension (or relax), does that help me?
  
  – Lupino
  Jan 24 at 12:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you mean, you don't know how many expansions are necessary? @nameuse{foo} will always take exactly 3 expansions to arrive at the expansion of foo, won't it?
  
  – schtandard
  Jan 24 at 13:00
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Imagine a table and for each cell of any that table, i want to store width, height, content. So my version of @namedef is def@mynamedef#1#2{expandaftergdefcsname cell-thetable-thec@row-thec@cell-#2endcsname{#1}} with #2 being the propety (content, width, height), and #1 the value. I sorta switched #1 and #2 so i can expand length registers prior to assignment into my property matrix using expandafter@mynamedefexpandafter{the@tempdima}{width} which stores (e.g.) 12mm as value of csname cell-1-2-2-widthendcsname.
  
  – Lupino
  Jan 24 at 13:12
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino I will try to understand what you are asking here, but it would be useful for you to edit your question and provide additional code on what does and doesn't work for you.
  
  – Steven B. Segletes
  Jan 24 at 13:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino See my edit. The use of 3xexpandafter in your MWE only produces 2 expansions. You would need 7xexpandafter to get the triple expansion you seek.
  
  – Steven B. Segletes
  Jan 24 at 13:38
  

  
  
  
  

 | 
show 1 more comment

1

You just need to give no initial definition to blafasel. If you want to test whether it has received a definition, just do

expandafterifxcsname blafaselendcsnamerelax

   <still not defined>%

else

   <is defined>%

fi

This exploits the fact that a token constructed with csname is made equivalent to relax if it has no previous definition.

share|improve this answer

answered Jan 24 at 13:05

egregegreg

727k8819223231

add a comment | 

1

@nameuse{blafasel} expands to csname blafaselendcsname, which you expand once again yielding blafasel. You then compare this to relax, which is different. You have three possibilities of solving your problem:

1. 
   

   You can expand blafasel once more:

   
   
   

   @namedef{blafasel}{relax}%
   
   expandafterexpandafterexpandafterexpandafter
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   Note that this ifx will always follow the true branch when the expansion blafasel starts with two equal tokens and is thus not a good test. Try @namedef{blafasel}{OOH, LOOK, AN ERROR!}, for example.

   
   


2. 
   

   You can define a different macro to compare it to:

   
   
   

   @namedef{blafasel}{relax}%
   
   def@test@macro{relax}%
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}@test@macro
   
       true
   
   else
   
       false
   
   fi
   
   

   
   


3. 
   

   You can initialize your macros to be the same as relax instead of a macro expanding to relax:

   
   
   

   def@namelet#1#2{expandafterletcsname #1endcsname#2}%
   
   @namelet{blafasel}relax
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   As egreg points out, you could just as well leave blafasel undefined (i.e. omit the first two lines of this code block), since csname will default to relax, when the macro is not defined.

   
   

share|improve this answer

edited Jan 24 at 13:09

answered Jan 24 at 12:52

schtandardschtandard

1,904718

add a comment | 

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

active

oldest

votes

active

oldest

votes

4

The problem you will confront will be that, unless you know in advance the types of arguments that may be passed to this test, they each may require differing numbers of expansions to finally reach the relax or not-relax condition.

Perhaps you need to fully expand your argument for the test:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

edeftmp{@nameuse{blafasel}}% MUST, HOWEVER, BE FULLY EXPANDABLE

expandafterifxtmprelax

   true

else

   false

fi



end{document}

Of course, this approach only works if the test argument is fully expandable.

---

Alternately, if it will always be a @nameuse that is part of the test, then the use of 3xexpandafter only produces 2 expansions. You need 7xexpandafter to get 3 expansions, resulting in a true test.

Rule: to get n expansions, you need 2^n - 1 instances of expandafter.

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterexpandafterexpandafter%

  expandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

share|improve this answer

edited Jan 24 at 16:42

answered Jan 24 at 12:18

Steven B. SegletesSteven B. Segletes

158k9204411

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks. I fear, i dont understand "fully expandable". my actual exampe is @namedef{blafaselc@mycounter}. The "value" of blasasel<x> can be a string, a dimension, a length, a number, a cs, or relax... Say, i know that blafasel1 is a string (or relax), blafasel2 is a dimension (or relax), does that help me?
  
  – Lupino
  Jan 24 at 12:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you mean, you don't know how many expansions are necessary? @nameuse{foo} will always take exactly 3 expansions to arrive at the expansion of foo, won't it?
  
  – schtandard
  Jan 24 at 13:00
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Imagine a table and for each cell of any that table, i want to store width, height, content. So my version of @namedef is def@mynamedef#1#2{expandaftergdefcsname cell-thetable-thec@row-thec@cell-#2endcsname{#1}} with #2 being the propety (content, width, height), and #1 the value. I sorta switched #1 and #2 so i can expand length registers prior to assignment into my property matrix using expandafter@mynamedefexpandafter{the@tempdima}{width} which stores (e.g.) 12mm as value of csname cell-1-2-2-widthendcsname.
  
  – Lupino
  Jan 24 at 13:12
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino I will try to understand what you are asking here, but it would be useful for you to edit your question and provide additional code on what does and doesn't work for you.
  
  – Steven B. Segletes
  Jan 24 at 13:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino See my edit. The use of 3xexpandafter in your MWE only produces 2 expansions. You would need 7xexpandafter to get the triple expansion you seek.
  
  – Steven B. Segletes
  Jan 24 at 13:38
  

  
  
  
  

 | 
show 1 more comment

4

The problem you will confront will be that, unless you know in advance the types of arguments that may be passed to this test, they each may require differing numbers of expansions to finally reach the relax or not-relax condition.

Perhaps you need to fully expand your argument for the test:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

edeftmp{@nameuse{blafasel}}% MUST, HOWEVER, BE FULLY EXPANDABLE

expandafterifxtmprelax

   true

else

   false

fi



end{document}

Of course, this approach only works if the test argument is fully expandable.

---

Alternately, if it will always be a @nameuse that is part of the test, then the use of 3xexpandafter only produces 2 expansions. You need 7xexpandafter to get 3 expansions, resulting in a true test.

Rule: to get n expansions, you need 2^n - 1 instances of expandafter.

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterexpandafterexpandafter%

  expandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

share|improve this answer

edited Jan 24 at 16:42

answered Jan 24 at 12:18

Steven B. SegletesSteven B. Segletes

158k9204411

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks. I fear, i dont understand "fully expandable". my actual exampe is @namedef{blafaselc@mycounter}. The "value" of blasasel<x> can be a string, a dimension, a length, a number, a cs, or relax... Say, i know that blafasel1 is a string (or relax), blafasel2 is a dimension (or relax), does that help me?
  
  – Lupino
  Jan 24 at 12:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you mean, you don't know how many expansions are necessary? @nameuse{foo} will always take exactly 3 expansions to arrive at the expansion of foo, won't it?
  
  – schtandard
  Jan 24 at 13:00
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Imagine a table and for each cell of any that table, i want to store width, height, content. So my version of @namedef is def@mynamedef#1#2{expandaftergdefcsname cell-thetable-thec@row-thec@cell-#2endcsname{#1}} with #2 being the propety (content, width, height), and #1 the value. I sorta switched #1 and #2 so i can expand length registers prior to assignment into my property matrix using expandafter@mynamedefexpandafter{the@tempdima}{width} which stores (e.g.) 12mm as value of csname cell-1-2-2-widthendcsname.
  
  – Lupino
  Jan 24 at 13:12
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino I will try to understand what you are asking here, but it would be useful for you to edit your question and provide additional code on what does and doesn't work for you.
  
  – Steven B. Segletes
  Jan 24 at 13:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino See my edit. The use of 3xexpandafter in your MWE only produces 2 expansions. You would need 7xexpandafter to get the triple expansion you seek.
  
  – Steven B. Segletes
  Jan 24 at 13:38
  

  
  
  
  

 | 
show 1 more comment

4

4

4

The problem you will confront will be that, unless you know in advance the types of arguments that may be passed to this test, they each may require differing numbers of expansions to finally reach the relax or not-relax condition.

Perhaps you need to fully expand your argument for the test:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

edeftmp{@nameuse{blafasel}}% MUST, HOWEVER, BE FULLY EXPANDABLE

expandafterifxtmprelax

   true

else

   false

fi



end{document}

Of course, this approach only works if the test argument is fully expandable.

---

Alternately, if it will always be a @nameuse that is part of the test, then the use of 3xexpandafter only produces 2 expansions. You need 7xexpandafter to get 3 expansions, resulting in a true test.

Rule: to get n expansions, you need 2^n - 1 instances of expandafter.

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterexpandafterexpandafter%

  expandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

share|improve this answer

edited Jan 24 at 16:42

answered Jan 24 at 12:18

Steven B. SegletesSteven B. Segletes

158k9204411

The problem you will confront will be that, unless you know in advance the types of arguments that may be passed to this test, they each may require differing numbers of expansions to finally reach the relax or not-relax condition.

Perhaps you need to fully expand your argument for the test:

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

edeftmp{@nameuse{blafasel}}% MUST, HOWEVER, BE FULLY EXPANDABLE

expandafterifxtmprelax

   true

else

   false

fi



end{document}

Of course, this approach only works if the test argument is fully expandable.

---

Alternately, if it will always be a @nameuse that is part of the test, then the use of 3xexpandafter only produces 2 expansions. You need 7xexpandafter to get 3 expansions, resulting in a true test.

Rule: to get n expansions, you need 2^n - 1 instances of expandafter.

documentclass{standalone}



makeatletter

parindentz@

@namedef{blafasel}{relax}





begin{document}

expandafterexpandafterexpandafterexpandafterexpandafter%

  expandafterexpandafterifx@nameuse{blafasel}relax

   true

else

   false

fi



end{document}

share|improve this answer

edited Jan 24 at 16:42

answered Jan 24 at 12:18

Steven B. SegletesSteven B. Segletes

158k9204411

share|improve this answer

share|improve this answer

edited Jan 24 at 16:42

edited Jan 24 at 16:42

edited Jan 24 at 16:42

answered Jan 24 at 12:18

Steven B. SegletesSteven B. Segletes

158k9204411

answered Jan 24 at 12:18

Steven B. SegletesSteven B. Segletes

158k9204411

answered Jan 24 at 12:18

Steven B. SegletesSteven B. Segletes

158k9204411

158k9204411

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks. I fear, i dont understand "fully expandable". my actual exampe is @namedef{blafaselc@mycounter}. The "value" of blasasel<x> can be a string, a dimension, a length, a number, a cs, or relax... Say, i know that blafasel1 is a string (or relax), blafasel2 is a dimension (or relax), does that help me?
  
  – Lupino
  Jan 24 at 12:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you mean, you don't know how many expansions are necessary? @nameuse{foo} will always take exactly 3 expansions to arrive at the expansion of foo, won't it?
  
  – schtandard
  Jan 24 at 13:00
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Imagine a table and for each cell of any that table, i want to store width, height, content. So my version of @namedef is def@mynamedef#1#2{expandaftergdefcsname cell-thetable-thec@row-thec@cell-#2endcsname{#1}} with #2 being the propety (content, width, height), and #1 the value. I sorta switched #1 and #2 so i can expand length registers prior to assignment into my property matrix using expandafter@mynamedefexpandafter{the@tempdima}{width} which stores (e.g.) 12mm as value of csname cell-1-2-2-widthendcsname.
  
  – Lupino
  Jan 24 at 13:12
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino I will try to understand what you are asking here, but it would be useful for you to edit your question and provide additional code on what does and doesn't work for you.
  
  – Steven B. Segletes
  Jan 24 at 13:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino See my edit. The use of 3xexpandafter in your MWE only produces 2 expansions. You would need 7xexpandafter to get the triple expansion you seek.
  
  – Steven B. Segletes
  Jan 24 at 13:38
  

  
  
  
  

 | 
show 1 more comment

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks. I fear, i dont understand "fully expandable". my actual exampe is @namedef{blafaselc@mycounter}. The "value" of blasasel<x> can be a string, a dimension, a length, a number, a cs, or relax... Say, i know that blafasel1 is a string (or relax), blafasel2 is a dimension (or relax), does that help me?
  
  – Lupino
  Jan 24 at 12:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you mean, you don't know how many expansions are necessary? @nameuse{foo} will always take exactly 3 expansions to arrive at the expansion of foo, won't it?
  
  – schtandard
  Jan 24 at 13:00
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Imagine a table and for each cell of any that table, i want to store width, height, content. So my version of @namedef is def@mynamedef#1#2{expandaftergdefcsname cell-thetable-thec@row-thec@cell-#2endcsname{#1}} with #2 being the propety (content, width, height), and #1 the value. I sorta switched #1 and #2 so i can expand length registers prior to assignment into my property matrix using expandafter@mynamedefexpandafter{the@tempdima}{width} which stores (e.g.) 12mm as value of csname cell-1-2-2-widthendcsname.
  
  – Lupino
  Jan 24 at 13:12
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino I will try to understand what you are asking here, but it would be useful for you to edit your question and provide additional code on what does and doesn't work for you.
  
  – Steven B. Segletes
  Jan 24 at 13:25
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Lupino See my edit. The use of 3xexpandafter in your MWE only produces 2 expansions. You would need 7xexpandafter to get the triple expansion you seek.
  
  – Steven B. Segletes
  Jan 24 at 13:38
  

  
  
  
  

Thanks. I fear, i dont understand "fully expandable". my actual exampe is @namedef{blafaselc@mycounter}. The "value" of blasasel<x> can be a string, a dimension, a length, a number, a cs, or relax... Say, i know that blafasel1 is a string (or relax), blafasel2 is a dimension (or relax), does that help me?

– Lupino
Jan 24 at 12:25

Thanks. I fear, i dont understand "fully expandable". my actual exampe is @namedef{blafaselc@mycounter}. The "value" of blasasel<x> can be a string, a dimension, a length, a number, a cs, or relax... Say, i know that blafasel1 is a string (or relax), blafasel2 is a dimension (or relax), does that help me?

– Lupino
Jan 24 at 12:25

What do you mean, you don't know how many expansions are necessary? @nameuse{foo} will always take exactly 3 expansions to arrive at the expansion of foo, won't it?

– schtandard
Jan 24 at 13:00

What do you mean, you don't know how many expansions are necessary? @nameuse{foo} will always take exactly 3 expansions to arrive at the expansion of foo, won't it?

– schtandard
Jan 24 at 13:00

Imagine a table and for each cell of any that table, i want to store width, height, content. So my version of @namedef is def@mynamedef#1#2{expandaftergdefcsname cell-thetable-thec@row-thec@cell-#2endcsname{#1}} with #2 being the propety (content, width, height), and #1 the value. I sorta switched #1 and #2 so i can expand length registers prior to assignment into my property matrix using expandafter@mynamedefexpandafter{the@tempdima}{width} which stores (e.g.) 12mm as value of csname cell-1-2-2-widthendcsname.

– Lupino
Jan 24 at 13:12

Imagine a table and for each cell of any that table, i want to store width, height, content. So my version of @namedef is def@mynamedef#1#2{expandaftergdefcsname cell-thetable-thec@row-thec@cell-#2endcsname{#1}} with #2 being the propety (content, width, height), and #1 the value. I sorta switched #1 and #2 so i can expand length registers prior to assignment into my property matrix using expandafter@mynamedefexpandafter{the@tempdima}{width} which stores (e.g.) 12mm as value of csname cell-1-2-2-widthendcsname.

– Lupino
Jan 24 at 13:12

@Lupino I will try to understand what you are asking here, but it would be useful for you to edit your question and provide additional code on what does and doesn't work for you.

– Steven B. Segletes
Jan 24 at 13:25

@Lupino I will try to understand what you are asking here, but it would be useful for you to edit your question and provide additional code on what does and doesn't work for you.

– Steven B. Segletes
Jan 24 at 13:25

@Lupino See my edit. The use of 3xexpandafter in your MWE only produces 2 expansions. You would need 7xexpandafter to get the triple expansion you seek.

– Steven B. Segletes
Jan 24 at 13:38

@Lupino See my edit. The use of 3xexpandafter in your MWE only produces 2 expansions. You would need 7xexpandafter to get the triple expansion you seek.

– Steven B. Segletes
Jan 24 at 13:38

 | 
show 1 more comment

1

You just need to give no initial definition to blafasel. If you want to test whether it has received a definition, just do

expandafterifxcsname blafaselendcsnamerelax

   <still not defined>%

else

   <is defined>%

fi

This exploits the fact that a token constructed with csname is made equivalent to relax if it has no previous definition.

share|improve this answer

answered Jan 24 at 13:05

egregegreg

727k8819223231

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1

You just need to give no initial definition to blafasel. If you want to test whether it has received a definition, just do

expandafterifxcsname blafaselendcsnamerelax

   <still not defined>%

else

   <is defined>%

fi

This exploits the fact that a token constructed with csname is made equivalent to relax if it has no previous definition.

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answered Jan 24 at 13:05

egregegreg

727k8819223231

add a comment | 

1

1

1

You just need to give no initial definition to blafasel. If you want to test whether it has received a definition, just do

expandafterifxcsname blafaselendcsnamerelax

   <still not defined>%

else

   <is defined>%

fi

This exploits the fact that a token constructed with csname is made equivalent to relax if it has no previous definition.

share|improve this answer

answered Jan 24 at 13:05

egregegreg

727k8819223231

You just need to give no initial definition to blafasel. If you want to test whether it has received a definition, just do

expandafterifxcsname blafaselendcsnamerelax

   <still not defined>%

else

   <is defined>%

fi

This exploits the fact that a token constructed with csname is made equivalent to relax if it has no previous definition.

share|improve this answer

answered Jan 24 at 13:05

egregegreg

727k8819223231

share|improve this answer

share|improve this answer

answered Jan 24 at 13:05

egregegreg

727k8819223231

answered Jan 24 at 13:05

egregegreg

727k8819223231

answered Jan 24 at 13:05

egregegreg

727k8819223231

727k8819223231

add a comment | 

add a comment | 

1

@nameuse{blafasel} expands to csname blafaselendcsname, which you expand once again yielding blafasel. You then compare this to relax, which is different. You have three possibilities of solving your problem:

1. 
   

   You can expand blafasel once more:

   
   
   

   @namedef{blafasel}{relax}%
   
   expandafterexpandafterexpandafterexpandafter
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   Note that this ifx will always follow the true branch when the expansion blafasel starts with two equal tokens and is thus not a good test. Try @namedef{blafasel}{OOH, LOOK, AN ERROR!}, for example.

   
   


2. 
   

   You can define a different macro to compare it to:

   
   
   

   @namedef{blafasel}{relax}%
   
   def@test@macro{relax}%
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}@test@macro
   
       true
   
   else
   
       false
   
   fi
   
   

   
   


3. 
   

   You can initialize your macros to be the same as relax instead of a macro expanding to relax:

   
   
   

   def@namelet#1#2{expandafterletcsname #1endcsname#2}%
   
   @namelet{blafasel}relax
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   As egreg points out, you could just as well leave blafasel undefined (i.e. omit the first two lines of this code block), since csname will default to relax, when the macro is not defined.

   
   

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edited Jan 24 at 13:09

answered Jan 24 at 12:52

schtandardschtandard

1,904718

add a comment | 

1

@nameuse{blafasel} expands to csname blafaselendcsname, which you expand once again yielding blafasel. You then compare this to relax, which is different. You have three possibilities of solving your problem:

1. 
   

   You can expand blafasel once more:

   
   
   

   @namedef{blafasel}{relax}%
   
   expandafterexpandafterexpandafterexpandafter
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   Note that this ifx will always follow the true branch when the expansion blafasel starts with two equal tokens and is thus not a good test. Try @namedef{blafasel}{OOH, LOOK, AN ERROR!}, for example.

   
   


2. 
   

   You can define a different macro to compare it to:

   
   
   

   @namedef{blafasel}{relax}%
   
   def@test@macro{relax}%
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}@test@macro
   
       true
   
   else
   
       false
   
   fi
   
   

   
   


3. 
   

   You can initialize your macros to be the same as relax instead of a macro expanding to relax:

   
   
   

   def@namelet#1#2{expandafterletcsname #1endcsname#2}%
   
   @namelet{blafasel}relax
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   As egreg points out, you could just as well leave blafasel undefined (i.e. omit the first two lines of this code block), since csname will default to relax, when the macro is not defined.

   
   

share|improve this answer

edited Jan 24 at 13:09

answered Jan 24 at 12:52

schtandardschtandard

1,904718

add a comment | 

1

1

1

@nameuse{blafasel} expands to csname blafaselendcsname, which you expand once again yielding blafasel. You then compare this to relax, which is different. You have three possibilities of solving your problem:

1. 
   

   You can expand blafasel once more:

   
   
   

   @namedef{blafasel}{relax}%
   
   expandafterexpandafterexpandafterexpandafter
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   Note that this ifx will always follow the true branch when the expansion blafasel starts with two equal tokens and is thus not a good test. Try @namedef{blafasel}{OOH, LOOK, AN ERROR!}, for example.

   
   


2. 
   

   You can define a different macro to compare it to:

   
   
   

   @namedef{blafasel}{relax}%
   
   def@test@macro{relax}%
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}@test@macro
   
       true
   
   else
   
       false
   
   fi
   
   

   
   


3. 
   

   You can initialize your macros to be the same as relax instead of a macro expanding to relax:

   
   
   

   def@namelet#1#2{expandafterletcsname #1endcsname#2}%
   
   @namelet{blafasel}relax
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   As egreg points out, you could just as well leave blafasel undefined (i.e. omit the first two lines of this code block), since csname will default to relax, when the macro is not defined.

   
   

share|improve this answer

edited Jan 24 at 13:09

answered Jan 24 at 12:52

schtandardschtandard

1,904718

@nameuse{blafasel} expands to csname blafaselendcsname, which you expand once again yielding blafasel. You then compare this to relax, which is different. You have three possibilities of solving your problem:

1. 
   

   You can expand blafasel once more:

   
   
   

   @namedef{blafasel}{relax}%
   
   expandafterexpandafterexpandafterexpandafter
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   Note that this ifx will always follow the true branch when the expansion blafasel starts with two equal tokens and is thus not a good test. Try @namedef{blafasel}{OOH, LOOK, AN ERROR!}, for example.

   
   


2. 
   

   You can define a different macro to compare it to:

   
   
   

   @namedef{blafasel}{relax}%
   
   def@test@macro{relax}%
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}@test@macro
   
       true
   
   else
   
       false
   
   fi
   
   

   
   


3. 
   

   You can initialize your macros to be the same as relax instead of a macro expanding to relax:

   
   
   

   def@namelet#1#2{expandafterletcsname #1endcsname#2}%
   
   @namelet{blafasel}relax
   
   expandafterexpandafterexpandafterifx@nameuse{blafasel}relax
   
       true
   
   else
   
       false
   
   fi
   
   

   
   
   

   As egreg points out, you could just as well leave blafasel undefined (i.e. omit the first two lines of this code block), since csname will default to relax, when the macro is not defined.

   
   

share|improve this answer

edited Jan 24 at 13:09

answered Jan 24 at 12:52

schtandardschtandard

1,904718

share|improve this answer

share|improve this answer

edited Jan 24 at 13:09

edited Jan 24 at 13:09

edited Jan 24 at 13:09

answered Jan 24 at 12:52

schtandardschtandard

1,904718

answered Jan 24 at 12:52

schtandardschtandard

1,904718

answered Jan 24 at 12:52

schtandardschtandard

1,904718

1,904718

add a comment | 

add a comment | 

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