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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