the difference between \def and \define

newer
Re: [NTG-context] Center-Aligment...

older
Re: [NTG-context] Center-Aligment...

Tim Li

15 Apr 2013 15 Apr '13

3:47 p.m.

In plain TeX, we always use \def for creating a new macro, but in ConTeXt, sometimes it won't work, especially when making own chapter titles. The \def can produce the error message like this : "Argument of \... has an extra }". \define in ConTeXt can solve this problem. What's the difference between \def and \define? Can I use \define to replace all \def?

Attachments:

attachment.html (text/html — 604 bytes)

Show replies by date

Wolfgang Schuster

15 Apr 15 Apr

4:04 p.m.

Am 15.04.2013 um 15:47 schrieb Tim Li :

...

In plain TeX, we always use \def for creating a new macro, but in ConTeXt, sometimes it won't work, especially when making own chapter titles. The \def can produce the error message like this : "Argument of \... has an extra }". \define in ConTeXt can solve this problem.

What's the difference between \def and \define? Can I use \define to replace all \def?

The \define command is a short form for \unexpanded\def which prevents commands to be expanded when used inside \edef or when passed to Lua. Most of the high level commands are created to be unexpanded and expandable commands are used for internal functions. Wolfgang

Marco Patzer

4:07 p.m.

On 2013–04–15 Tim Li wrote:

...

What's the difference between \def and \define?

\define is basically the same as \unexpanded\def. It uses a slightly different syntax for specifying optional arguments: \define[3]\foo{First: #1, Second: #2, Third: #3} \unexpanded\def\foo#1#2#3{First: #1, Second: #2, Third: #3} Furthermore, \define displays a message if the command is already defined: system > command '\foo' is already defined However, ConTeXt happily overwrites the existing macro.

...

Can I use \define to replace all \def?

There is \defineexpandable, which uses the same syntax as \define, but it's a simple \def, without \unexpanded which is the closest replacement. I don't think named parameters are possible with \define, but maybe I'm mistaken. \def\bar#first#second{First: #first, Second: #second} For you information, there's also \starttexdefinition mycmd #1 … \stoptexdefinition \starttexdefinition mycmd $#first #second … \stoptexdefinition \starttexdefinition unexpanded mycmd #first #second … \stoptexdefinition Marco

Hans Hagen

4:12 p.m.

On 4/15/2013 4:07 PM, Marco Patzer wrote:

...

I don't think named parameters are possible with \define, but maybe I'm mistaken.

just use suffix .mkvi or put "% macros=mkvi" at the top of your file ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

Wolfgang Schuster

4:21 p.m.

Am 15.04.2013 um 16:12 schrieb Hans Hagen :

...

On 4/15/2013 4:07 PM, Marco Patzer wrote:

...
I don't think named parameters are possible with \define, but maybe I'm mistaken.

just use suffix .mkvi or put "% macros=mkvi" at the top of your file

Marco tries to do something like \define[3]\Test{#one#two#three} which doesn’t work. Wolfgang

Hans Hagen

16 Apr 16 Apr

10:42 a.m.

On 4/15/2013 4:21 PM, Wolfgang Schuster wrote:

...

Am 15.04.2013 um 16:12 schrieb Hans Hagen :

...
On 4/15/2013 4:07 PM, Marco Patzer wrote:

...
I don't think named parameters are possible with \define, but maybe I'm mistaken.

just use suffix .mkvi or put "% macros=mkvi" at the top of your file

Marco tries to do something like

\define[3]\Test{#one#two#three}

which doesn’t work.

hm, ok, do \define is not mkvi then ... too messy to catch that one too ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

Marco Patzer

11:05 a.m.

On 2013–04–16 Hans Hagen wrote:

...

...
Marco tries to do something like

\define[3]\Test{#one#two#three}

which doesn’t work.

hm, ok, do \define is not mkvi then ... too messy to catch that one too

No need to bother with that. I was just pointing out the differences between \def and \define for Tim. And named parameters is something \define can't do. It doesn't make sense to use named parameters with \define, since you explicitly pass the parameter *number* in brackets. You cannot refer to a number by name. Well, you could theoretically, but I'd strongly object. Marco

Thomas A. Schmitz

11:10 a.m.

On 04/16/2013 11:05 AM, Marco Patzer wrote:

...

It doesn't make sense to use named parameters with \define, since you explicitly pass the parameter*number* in brackets. You cannot refer to a number by name. Well, you could theoretically, but I'd strongly object.

Just out of curiosity: why would you object? In Lua, we have the syntax function whatever(one, two, three) do something with(one, two, three) end I'm not lobbying for define to have something similar, I just want to point out that it would be in the spirit of convergence between ConTeXt and Lua. It certainly isn't an urgent need, but having \define[one,two,three] wouldn't be absurd, now would it? Thomas

Marco Patzer

12:11 p.m.

On 2013–04–16 Thomas A. Schmitz wrote:

...

I'm not lobbying for define to have something similar, I just want to point out that it would be in the spirit of convergence between ConTeXt and Lua. It certainly isn't an urgent need, but having

\define[one,two,three]

wouldn't be absurd, now would it?

Sorry, misunderstanding on my part. That one looks fine. I thought we're talking about translating the number to words, which wouldn't make any sense: \define[3]\foo{#one, #two, #three} I still don't think it's necessary to use named parameters with \define. For modules most likely \def, \setvalue or texdefinition are being used and \define for in-document markup, wherefore numbered parameters are perfectly fine. The only thing that could be improved is a definition which doesn't interfere with \asciimode, but that's low priority and can easily be worked around. Marco

Hans Hagen

6:03 p.m.

On 4/16/2013 12:11 PM, Marco Patzer wrote:

...

On 2013–04–16 Thomas A. Schmitz wrote:

...
I'm not lobbying for define to have something similar, I just want to point out that it would be in the spirit of convergence between ConTeXt and Lua. It certainly isn't an urgent need, but having

\define[one,two,three]

wouldn't be absurd, now would it?

Sorry, misunderstanding on my part. That one looks fine. I thought we're talking about translating the number to words, which wouldn't make any sense:

\define[3]\foo{#one, #two, #three}

I still don't think it's necessary to use named parameters with \define. For modules most likely \def, \setvalue or texdefinition are being used and \define for in-document markup, wherefore numbered parameters are perfectly fine. The only thing that could be improved is a definition which doesn't interfere with \asciimode, but that's low priority and can easily be worked around.

It's also messy (in parsing): \define[#one,#two]\test{#one#two} there we have to collect and move the test backwards. Also, names defeats the use of the one number becoming multiple #'s so it then close to \define\test[#one,#two]{#one#two} which is nearly \def\test[#one,#two]{#one#two} apart from the checking, so i decided to provide this: \checked\def \whatevera#alpha#beta{#alpha + #beta} \checked\edef\whatevera#alpha#beta{#beta + #alpha} \unique \def \whateverb#alpha#beta{#alpha + #beta} \unique \edef\whateverb#alpha#beta{#beta + #alpha} \whatevera{1}{2}\par \whateverb{1}{2}\par (can be used with \def \edef \xdef \gdef \udef \uedef \uxdef and \ugdef) Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

Hans Hagen

12:34 p.m.

On 4/16/2013 11:10 AM, Thomas A. Schmitz wrote:

...

On 04/16/2013 11:05 AM, Marco Patzer wrote:

...
It doesn't make sense to use named parameters with \define, since you explicitly pass the parameter*number* in brackets. You cannot refer to a number by name. Well, you could theoretically, but I'd strongly object.

Just out of curiosity: why would you object? In Lua, we have the syntax

function whatever(one, two, three) do something with(one, two, three) end

I'm not lobbying for define to have something similar, I just want to point out that it would be in the spirit of convergence between ConTeXt and Lua. It certainly isn't an urgent need, but having

\define[one,two,three]

wouldn't be absurd, now would it?

there is a commented blob that implements thinsg like this \starttext \define[2]\whatevera{#1+#2} \whatevera{A}{B} \define[me][too][2]\whateverb{#1+#2+#3+#4} \whateverb[A]{B}{C} \whateverb[A][B]{C}{D} \define[alpha][beta][gamma][delta]\whateverc{#1+#2+#3+#4} \whateverc[P][Q] \stoptext but it's just an old idea. Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

Alan BRASLAU

1:14 p.m.

Since the question has been raised about understanding \define, etc. indeed some use remains a bit unclear (to me). On Tue, 16 Apr 2013 12:34:48 +0200 Hans Hagen wrote:

...

there is a commented blob that implements thinsg like this

\starttext \define[2]\whatevera{#1+#2} \whatevera{A}{B} \define[me][too][2]\whateverb{#1+#2+#3+#4} \whateverb[A]{B}{C} \whateverb[A][B]{C}{D} \define[alpha][beta][gamma][delta]\whateverc{#1+#2+#3+#4} \whateverc[P][Q] \stoptext

but it's just an old idea.

I am perhaps a bit bewildered today... but I do not understand the above. It gets too tricky for me! In fact, I do not understand well the handling of arguments, especially optional variants. For example, \define[1]\Index{\index{#1}#1} can be handy. But let's say that I want to be able to use a variant: \Index[alpha]{$\alpha$} (\index[alpha]{$\alpha$}$\alpha$) Or, maybe, I might like to handle authors: \define[2]\Author{\index{#2, #1}#1 #2} \Author{Thomas A.}{Schmitz} But what if I were to type \Author{Aristotle}? Alan P.S. I indeed like the idea of the suggestion: \define[one,two,three]\whatever{first: #one second: #two third: #three} On 4/16/2013 11:10 AM, Thomas A. Schmitz wrote:

...

It certainly isn't an urgent need, but having

\define[one,two,three]

wouldn't be absurd, now would it?

Hans Hagen

2:01 p.m.

On 4/16/2013 1:14 PM, Alan BRASLAU wrote:

...

Since the question has been raised about understanding \define, etc. indeed some use remains a bit unclear (to me).

On Tue, 16 Apr 2013 12:34:48 +0200 Hans Hagen wrote:

...
there is a commented blob that implements thinsg like this

\starttext \define[2]\whatevera{#1+#2} \whatevera{A}{B} \define[me][too][2]\whateverb{#1+#2+#3+#4} \whateverb[A]{B}{C} \whateverb[A][B]{C}{D} \define[alpha][beta][gamma][delta]\whateverc{#1+#2+#3+#4} \whateverc[P][Q] \stoptext

but it's just an old idea.

I am perhaps a bit bewildered today... but I do not understand the above. It gets too tricky for me!

that's why it's commented code -) \define [optional-arg-1-default][optional-arg-2-default]...[number of {} args] but .. not likely to become enabled anyway (was an experiment)

...

Or, maybe, I might like to handle authors: \define[2]\Author{\index{#2, #1}#1 #2} \Author{Thomas A.}{Schmitz} But what if I were to type \Author{Aristotle}?

the [] are optional with an optional default

...

\define[one,two,three]\whatever{first: #one second: #two third: #three}

that's not too complex to implement (as mkvi) if there's enough votes for it

...

On 4/16/2013 11:10 AM, Thomas A. Schmitz wrote:

...
It certainly isn't an urgent need, but having

\define[one,two,three]

wouldn't be absurd, now would it?

Marco Patzer

15 Apr 15 Apr

4:26 p.m.

On 2013–04–15 Hans Hagen wrote:

...

...
I don't think named parameters are possible with \define, but maybe I'm mistaken.

just use suffix .mkvi or put "% macros=mkvi" at the top of your file

That's how to enable named parameters for \def. I was talking about \define. The arguments are provided as a number in brackets, which makes it hard to refer to them by name: %% fails, of course \define[2]\foo{#first, #second} Marco

4387

Age (days ago)

4388

Last active (days ago)

List overview

Download

13 comments

6 participants

participants (6)

Alan BRASLAU
Hans Hagen
Marco Patzer
Thomas A. Schmitz
Tim Li
Wolfgang Schuster