Live LaTeX previewing with Chocolat and Skim.app

init.js

/*!
 * Experimental Chocolat mixins
 * Copyright(c) 2012 Torsten Grust <torsten.grust@gmail.com>
 */

var fs = require('fs');
var path = require('path');
var spawn = require('child_process').spawn;

var flashLaTeX = require('./tex.js').flashLaTeX;


/* Storage keys */
var isActive     = '__LaTeX_Flash_active__';
var retryPending = '__LaTeX_Flash_pending__';
var isTeXing     = '__LaTeX_Flash_texing__';

/* retry TeXing after this many ms */
var retryInterval = 100;

/* LaTeX Flash working directory */
var flashWorkingDirectory = '.flashchoc';

/* toggle Flash LaTeX, initialization */
Hooks.addMenuItem('Actions/Teggy/Start LaTeX Flash', 'control-option-command-f',
  function() {
    var doc = Document.current(),  
        transient = Storage.transient();                     

    /* only continue for LaTeX buffers */
    if ('latex.tex.text'.indexOf(doc.rootScope()))
      return;
    
    /* only continue if buffer is associated with a file */
    if (!doc.path())
      return;
    var texDirectory = path.dirname(doc.path());  /* directory component of LaTeX source */

    transient.set(isTeXing, false);
    
    /* toggle LaTeX flash activity */
    var active = !transient.get(isActive);  
    transient.set(isActive, active);
    Alert.notify({
      title:    'LaTeX Flash',
      subtitle: active ? 'is running' : 'has been stopped',
      body:     'Working directory is ' + texDirectory
    });

    if (!active)  
      return;
    
    /* establish LaTeX Flash working directory if needed */
    var flashDirectory = path.join(texDirectory, flashWorkingDirectory);
    if (!(fs.existsSync(flashDirectory) && 
          fs.statSync(flashDirectory).isDirectory())) {
      fs.mkdirSync(flashDirectory);    
    }
    
    /* first trigger LaTeX format recompilation, then flash for the first time */
    flash(true);
    flash(false);
})


/* trigger on-the-fly LaTeX recompilation */
function flash(ini) {
  var doc = Document.current(),   
      transient = Storage.transient(),
      error;
      
  /* only continue if LaTeX Flash is active */
  if (!transient.get(isActive))
    return null;
    
  /* only continue for LaTeX buffers */
  if ('latex.tex.text'.indexOf(doc.rootScope()))
    return null;

  /* only continue if buffer is associated with a file */
  if (!doc.path())
    return null;
  var texDirectory = path.dirname(doc.path());  /* directory component of LaTeX source */

  /* only continue if no other TeX run is active */
  if (transient.get(isTeXing))
  {          
    if (transient.get(retryPending))
      return null;
    transient.set(retryPending, true);    
    /* retry in a little while ... */
    setTimeout(function() { transient.set(retryPending, false); flash(ini); }, 
               retryInterval);      
    return null;
  }
  

  Recipe.run(function(recipe) {
    var lineNo, 
        error;
    
    lineNo = ini ?
               0 :
               recipe.lineIndexesForCharacterRange(recipe.selection).location + 1;
      
    flashLaTeX(transient, doc.text, texDirectory, lineNo);
  })
}

/* Flash LaTeX support: on-the-fly recompilation
   (initial code written during ICFP 2012, Copenhagen) 
*/
Hooks.onInsertText(function(c, editor) {
  /* trigger LaTeX recompilation */
  flash(false);
})

tex.js

/*!
 * Chocolate mixin for LaTeX Flash
 * Copyright(c) 2012 Torsten Grust <torsten.grust@gmail.com>
 * 
 * Initial code written during ICFP 2012, Copenhagen
 */

/* spawning the TeX process */
var child_process = require('child_process');
/* file I/O */
var fs = require('fs');
/* path handling */
var path = require('path');
/* Haskell-style array processing */ 
var prelude = require('./lib/prelude');

/* LaTeX Flash working directory */
var flashWorkingDirectory = '.flashchoc';

var isTeXing = '__LaTeX_Flash_texing__';

var flashLaTeX;
exports.flashLaTeX = flashLaTeX = function(transient, source, texDirectory, lineNo) {
  var flashDirectory = path.join(texDirectory, flashWorkingDirectory);  

  var preamble_body = source.split('\\begin{document}'),
      preamble = preamble_body[0],
      body = preamble_body[1];
  
  var begin_document = prelude.lines(preamble).length,
      inside_preamble = lineNo < begin_document;
  
  if (inside_preamble) {
    preamble = preamble +
               '\\usepackage{flashmate}' +
               '\\latexdump' +
               '\\begin{document}\\end{document}';      
          
    fs.writeFileSync(path.join(flashDirectory, 'preamble.tex'), preamble);

    if (transient.get(isTeXing))
      return;
      
    transient.set(isTeXing, true);
    
    return child_process.execFile(
        '/usr/texbin/pdfetex', 
        ['-ini',
         '-jobname=choc',
         '-output-directory', flashDirectory,
         '-interaction', 'batchmode',
         '&pdflatex',
         '\\input', path.join(flashDirectory, 'preamble')
        ],
        { cwd: texDirectory,
          timeout: 10000 
        },
        function(error, stdout, stderr) { 
          transient.set(isTeXing, false);
          if (!error) {
            body = '{\\Large\\ttfamily Recompiling \\LaTeX{} preamble\\dots}\n';
            runLaTeXviewPDF(transient, body, texDirectory, 1);          
          }
        });
  } 

  else {
  
    var cursor = lineNo - begin_document,              /* cursor = 0 if on \begin{document} line */
        sections = body.split(/\\section\{|\\chapter\{/);  /* array of sections */
        
    var section_breaks = 
      prelude.scanl(function(b, s) { return b + prelude.lines(s).length - 1}, 
                    0, 
                    sections);
    
    /* determine top and bottom line of cursor's section */
    var section = 
      prelude.head(
        prelude.filter(function(s) { return (s[0] <= cursor && cursor < s[1]) }, 
                       prelude.zip(section_breaks, 
                                   prelude.drop(1, section_breaks))));
    if (section) {
      var top = prelude.max(0, section[0]),
          bot = section[1];
    
      /* extract body slice of affected section */
      body = prelude.unlines(prelude.lines(body).slice(top, bot));
      
      return runLaTeXviewPDF(transient, body, texDirectory, cursor - top);
    }
  }
}



/* compile TeX body and view PDF */
function runLaTeXviewPDF(transient, body, texDirectory, lineNo) {
  var flashDirectory = path.join(texDirectory, flashWorkingDirectory);  
  
  fs.writeFileSync(path.join(flashDirectory, 'body.tex'), 
                   '\\begin{document}\n' + 
                   body +
                   '\n\\end{document}\n');

  if (transient.get(isTeXing))
    return;

  transient.set(isTeXing, true);    
  
  return child_process.execFile(
      '/usr/texbin/pdfetex', 
      ['-synctex=1',
       '-shell-escape',
       '-output-format', 'pdf',
       '-jobname=body',
       '-output-directory', flashDirectory,
       '-interaction', 'nonstopmode',
       '-fmt', path.join(flashDirectory, 'choc'),
       path.join(flashDirectory, 'body')
      ],
      { cwd: texDirectory,
        timeout: 10000 
      },
      function(error, stdout, stderr) {
        transient.set(isTeXing, false);
        if (!error) {
          child_process.execFile(
            '/Applications/Skim.app/Contents/SharedSupport/displayline',
            ['-r', '-b', '-g',
             lineNo.toString(),
             'body.pdf',
             'body.tex'
            ],
            { cwd: flashDirectory }
            );
        }
      });
}