Re: \inputif(file)exist(s)

["Procházka Lukáš Ing. - Pontex s. r. o." <LPr@pontex.cz>]

... Great, thank you.

Lukas


On Thu, 03 May 2012 17:41:18 +0200, Aditya Mahajan <adityam@umich.edu> wrote:

> On Thu, 3 May 2012, Procházka Lukáš Ing. - Pontex s. r. o. wrote:
>
>> Hello,
>>
>> just a quick question - is there a command like "\inputif(file)exist(s)",
>> which will \input a file if it exists, i.e. with no error if it doesn't?
>
> \readfile.
>
> From file-res.mkvi
>
> %D \macros
> %D   {readfile,ReadFile}
> %D
> %D One cannot be sure if a file exists. When no file can be
> %D found, the \type{\input} primitive gives an error message
> %D and switches to interactive mode. The macro \type{\readfile}
> %D takes care of non||existing files. This macro has two faces.
> %D
> %D \starttyping
> %D \ReadFile {filename}
> %D \readfile {filename} {before loading} {not found}
> %D \stoptyping
> %D
> %D Many \TEX\ implementations have laid out some strategy for
> %D locating files. This can lead to unexpected results,
> %D especially when one loads files that are not found in the
> %D current directory. Let's give an example of this. In
> %D \CONTEXT\ illustrations can be defined in an external file.
> %D The resizing macro first looks if an illustration is defined
> %D in the local definitions file. When no such file is found,
> %D it searches for a global file and when this file is not
> %D found either, the illustration itself is scanned for
> %D dimensions. One can imagine what happens if an adapted,
> %D localy stored illustration, is scaled according to
> %D dimensions stored somewhere else.
> %D
> %D When some \TEX\ implementation starts looking for a file, it
> %D normally first looks in the current directory. When no file
> %D is found, \TEX\ starts searching on the path where format
> %D and|/|or style files are stored. Depending on the implementation
> %D this can considerably slow down processing speed.
> %D
> %D In \CONTEXT, we support a project||wise ordening of files.
> %D In such an approach it seems feasible to store common files
> %D in a lower directory. When for instance searching for a
> %D general layout file, we therefore have to backtrack.
> %D
> %D These three considerations have lead to a more advanced
> %D approach for loading files.
> %D
> %D We first present an earlier implementation of
> %D \type{\readfile}. This command backtracks parent
> %D directories, upto a predefined level. Users can change this
> %D level (on the commandline using a directive); we default to~3.
> %D
> %D We use \type{\normalinput} instead of \type{\input}
> %D because we want to be able to redefine the original
> %D \type{\input} when needed, for instance when loading third
> %D party libraries.
>
>
> Aditya


-- 
Ing. Lukáš Procházka [mailto:LPr@pontex.cz]
Pontex s. r. o.      [mailto:pontex@pontex.cz] [http://www.pontex.cz]
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147 14 Praha 4

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