EVpath - short documentation ============================ Written by Giuseppe Ghibò © 1994 by Giuseppe Ghibò ----------- Description ----------- 1) Environment variables may have any length. ------------------------------------------ The environment variable used to specify a path may have any length (according to the size of the memory specified into Alloc_EnvPath()). Of course if we specify the environment variable with the AmigaDOS command SetEnv, the length of the var is truncated to 255 chars, but we can set the Environment variable using for instance an Editor; in such case we may have variables of arbitrary length. 2) Recursively path searching. --------------------------- If we append a * or a ** after a path element name, then such name is searched recursively for sub-directories. The char * is for one-level directory searching, while the ** is for searching into all the sub-dirs. Note that ** allow only a maximum of 10 level subdirectories (should be enough, but it can be modified changing the macro MAX_RECURS_DIR into the file EVPaths.c). Searching of subdirectories is executed when the function Init_EnvPath() is called and it is performed only _ONCE_ for every time we run the program, so if we append the ** to a directory which contains many (note `many' not `a few') non-reorganized sub-dirs, this can _slightly_ slow down the startup of the program. Of course isn't a good idea to use path such as: .,dh0:**,dh1:**,dh2:** although this could give an idea of how much time is needed to scan all the sub-directories of the whole hard disk (you can try this path using TeXWhereIs). For instance suppose to have the following path: TeX:texinputs**,TeX:macros* In such example, then the path list will became, for instance TeX:texinputs TeX:texinputs/one TeX:texinputs/one/one TeX:texinputs/one/one/two TeX:texinputs/one/one/two/three TeX:texinputs/one/one/two/three/four . . . TeX:texinputs/two TeX:texinputs/two/one TeX:texinputs/two/one/two . . . TeX:texinputs/macro TeX:texinputs/macro/one TeX:texinputs/macro/two TeX:texinputs/macro One of the most advantage of using the chars * and ** is that we don't have to change the var contents every time we install a new macro package. Since there are many macro packages for TeX, it is a good idea to keep each macro package into his own directory. For instance the LaTeX 2e macro packages contains also many sub-tools, and is a good idea to keep each tool into his own directory (easy to update) rather than to put thousands of files into TeX:texinputs/. For instance with TeX:texinputs/LaTeX2e* we match TeX:texinputs/LaTeX2e TeX:texinputs/LaTeX2e/tools TeX:texinputs/LaTeX2e/graphics TeX:texinputs/LaTeX2e/babel and so on. Note that there is also some synonymous for * and **: --------------------------------- | Char | searching | --------------------------------- | * | one-level directories | | ** | all sub-directories | | #? | one-level directories | | #?> | all sub-directories | | *> | all sub-directories | --------------------------------- Note also that chars * and ** (or synonymous) don't specifies wildcards; e.g. specifying TeX:macro/ltx*my we don't include every directory which matches the string `ltx*my'. Specifing TeX:texinputs** or TeX:texinputs/** is exactly the same thing, as well TeX:texinputs or TeX:texinputs/. 3) Recursively environment variable searching ------------------------------------------ In the path of an environment variables, we may also specify the name of another environment variable. For instance specifying the following path .,TeX:texinputs,$MYPATH,TeX:macros then the contents of the environment variable MYPATH will be added to the path list. Note that MYPATH could cointain another environment variable and so on. Up to 5 level of environment variables recursion are allowed (should be enough, but this value can also be changed changing the macro MAX_RECURS_VAR in EVpaths.c). Closed loop and duplicated entries are ignored. For instance setenv VARONE one,"$"VARTWO setenv VARTWO two,"$"VARTHREE setenv VARTHREE three,"$"VARFOUR setenv VARFOUR four,"$"VARFIVE setenv VARFIVE five,"$"VARSIX setenv VARSIX six,"$"SEVEN setenv SEVEN seven In such case if we use the variable VARONE, then we obtain the following path list one two three four five i.e. since recursive searching of environment variables is limited to 5, the two other variables `VARSIX' and `VARSEVEN' are simply ignored. Note that enclosing of $ between quotes is needed because otherwise the Shell expand the env variable (if it exists). This mean that quotes aren't needed if we use an editor to set the argument of an environment variable. Closed loop are also ignored, for instance if we consider setenv TEXINPUTS .,tex:texinputs,"$"MFINPUTS setenv MFINPUTS .,mf:mfinputs,"$"TEXINPUTS if we use TEXINPUTS then the path list will contain tex:texinputs mf:mfinputs otherwise if we use MFINPUTS the path list will contain mf:mfinputs tex:texinputs What we can do with a such features? We may specify path using TWO environment variables. For instance suppose that the variable TEXINPUTS contains: .,$MYPATH,TeX:texinputs,TeX:LaTeX,TeX:LaTeX2e* then we may set for instance the env var MYPATH to `mymacro' and then run TeX or MF. Suppose now we want to use the files contained into the directory `mymacro2'. In such case we have just to change the var MYPATH without to change the whole contents of TEXINPUTS. 4) Path separators --------------- Path separators recognized are , ; SPACES TABs LFs FFs or any combinations of them. For instance we may have the following path TeX:texinputs, TeX:macros** TeX:latex2e*; CWeb:macros MF:inputs* ^L^L MyTeX:mymacros and so on. 5) Names containing , ; or SPACES or TABS -------------------------------------- If a path name contains a space or , or ; we must to enclose such name into quotes. For instance: "The LaTeX", "this,, ,,,,dirs" "Another;;;;;;;one" Note that if a quote is leaved open then the path is taken as a whole path until a LF or FF is encountered. 6) Current dir. ------------ To include the current dir into the path we may use one of the following symbols: . "" "." Note that Unix like syntax such as: ./mypath -> directory `mypath' in the current dir and ../mypath -> directory `mymath' in the parent dir. are supported too. 7) Default path. ------------- If the path of the environment variable superseed the default path we may include the default path at an arbitrary position. For instance: default path = "MF:inputs,MF:ams/fonts/symbols" MFINPUTS = .,MF:mfinputs,?,CTAN:mfinputs then the resulting path list will be: `' (current dir) `MF:mfinputs' `MF:inputs' (from default path) `MF:ams/fonts/symbols' (from default path) `CTAN:mfinputs' 8) Duplicated entries are ignored. For instance using the following path .,".","",TeX:inputs,MF:inputs,TeX:inputs,MF:inputs the path list will contain only the following entries: `' (current) TeX:inputs MF:inputs this means that a file isn't searched into the current dir or in the directory TeX:inputs or MF:inputs only _ONCE_. Note that although TeX:inputs/ and TeX:inputs are treated in the same way, they aren't recognized as same for the purpose to avoid duplicated entries. 9) Compatibility with OS 1.3. -------------------------- EVPaths routines are fully compatible with OS 1.3. Since many TeX related programs still works with OS 1.3 it was a pity to loose the OS 1.3 compatibility only for the presence of the EVPaths routines...