Sunday, September 30, 2007

SEEing LaTeX 11: Typesetting Extended

In installment 10 of this series, I refactored the shell scripts used to compile and view a LaTeX document from SubEthaEdit. To change how a LaTeX document is compiled or viewed, it is now only necessary to change a variable, rather than messing around with the logic of the script. Let's take things a step further.

The relevant variables in the script are LATEX, PRODUCT_TYPE, and VIEWER. Their values in the script shown before were to use latexmk to build a PDF and PDFView to display it. However, other settings are possible. For example, setting
LATEX='pdflatex "$FILE"'
builds a PDF using pdflatex and shows it in Preview. These settings would be quite suitable for a "vanilla" installation, assuming no extras are installed beyond TeX.

A more flexible approach is to use those vanilla settings as defaults, and allow them to be overridden, giving
Now, if we run the script from the shell, we can set environment variables to change how the script does its work.

Within SEE, the environment variables will be provided by the AppleScript that runs the script. The change is relatively simple: we extend the string that calls our shell script to also set the environment variables. Since a number of minor changes to the AppleScript have accumulated, I'll show the whole thing:
tell application "SubEthaEdit"
    if exists path of front document then
        if modified of front document then
                save front document
            end try
        end if
        set filePath to path of front document
        set lineNumber to startLineNumber of selection of front document
        set modeResources to resource path of mode of front document
        error "You have to save the document first"
    end if
end tell

set buildScript to prependEnvironment onto (join of {quotedForm for (modeResources & "/Scripts/shell/"), quotedForm for filePath, lineNumber} by space)

do shell script buildScript

on seescriptsettings()
    return {displayName:"Typeset and View PDF", shortDisplayName:"Typeset", keyboardShortcut:"@b", toolbarIcon:"ToolbarIconBuildAndRun", inDefaultToolbar:"yes", toolbarTooltip:"Typeset and view the current document", inContextMenu:"no"}
end seescriptsettings

on join of tokenList by delimiter
    set oldTIDs to text item delimiters of AppleScript
    set text item delimiters of AppleScript to delimiter
    set joinedString to tokenList as string
    set text item delimiters of AppleScript to oldTIDs
    return joinedString
end join

on quotedForm for baseString  
    quote & baseString & quote
end quotedForm

to prependEnvironment onto scriptString
    "export SEE_LATEX_COMPILER='latexmk -pdf -quiet \"$FILE\"'; export SEE_LATEX_PRODUCT_TYPE=pdf; export SEE_LATEX_VIEWER='/Applications/ \"$LINE\" \"$PRODUCT\" \"$FILE\"';" & scriptString
end prependEnvironment

The basic strategy is still to construct a string that calls our shell script and feed it into do shell script. The string is changed in two ways. First, since the shell script now takes a line number as a second argument, I get the current line from SEE and pass it in. Second, and of more immediate interest, I set the environment variables and prepend those to the earlier buildScript. I've simplified the construction by defining join, quotedForm, and prependEnvironment handlers.

PrependEnvironment sets the SEE_LATEX_COMPILER, SEE_LATEX_PRODUCT_TYPE, and SEE_LATEX_VIEWER environment variables, customizing the behavior of the shell script. In the above AppleScript, I have set the environment so that latexmk and Skim are used to build and view a PDF.

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