JS1k: The JavaScript code golfing competition

D=document,A='textarea',r='replace',p=[];D.body.innerHTML='<'+A+' id=t rows=10 cols=80>var syn="tax"; // hl</'+A+'><br><button onclick="h()">hl</button><pre id=p></pre>';function s(c,r){return '<span style="color:#'+c+'">'+(r||'$1')+'</span>'}function h(){D.getElementById('p').innerHTML=D.getElementById('t').value[r](/</g,'&lt;')[r](/>/g,'&gt;')[r](/\\\\/g,'<b')[r](/\\\//g,'<l')[r](/\\'/g,'<q')[r](/\\"/g,'<d')[r](/([\[({=:]\s*?)\/(?![\/\*])/g,'$1<r/')[r](/\/\*[\s|\S]*?\*\/|\/\/.*|<r\/.+?\/\w*|".*?"|'.*?'/g,function(m){return "r"+p.push(m)+">"})[r](/((&[lg]t;|[&\/+\-*=?:.,;()\[\]{}|%^!])+)/g,s('17b'))[r](/\b(break|case|catch|continue|default|delete|do|else|false|finally|for|function|if|in|instanceof|new|return|switch|this|throw|true|try|typeof|var|void|while|with)\b/gi,s('f0b'))[r](/\b(0x[\da-f]+|\d+)\b/g,s('d83'))[r](/r(\d+)>/g,function(m,n){b=p[n-1];return b.match(/^\/[\/*]/)?s('666',b):b.match(/^["']/)?s('719',b):s('6a0',b)})[r](/<r/g,"")[r](/<q/g,"\\'")[r](/<d/g,'\\"')[r](/<l/g,'\\/')[r](/<b/g,'\\\\')}h()

RD1kb2N1bWVudCxBPSd0ZXh0YXJlYScscj0ncmVwbGFjZScscD1bXTtELmJvZHkuaW5uZXJIVE1MPSc8JytBKycgaWQ9dCByb3dzPTEwIGNvbHM9ODA+dmFyIHN5bj0idGF4IjsgLy8gaGw8LycrQSsnPjxicj48YnV0dG9uIG9uY2xpY2s9ImgoKSI+aGw8L2J1dHRvbj48cHJlIGlkPXA+PC9wcmU+JztmdW5jdGlvbiBzKGMscil7cmV0dXJuICc8c3BhbiBzdHlsZT0iY29sb3I6IycrYysnIj4nKyhyfHwnJDEnKSsnPC9zcGFuPid9ZnVuY3Rpb24gaCgpe0QuZ2V0RWxlbWVudEJ5SWQoJ3AnKS5pbm5lckhUTUw9RC5nZXRFbGVtZW50QnlJZCgndCcpLnZhbHVlW3JdKC88L2csJyZsdDsnKVtyXSgvPi9nLCcmZ3Q7Jylbcl0oL1xcXFwvZywnPGInKVtyXSgvXFxcLy9nLCc8bCcpW3JdKC9cXCcvZywnPHEnKVtyXSgvXFwiL2csJzxkJylbcl0oLyhbXFsoez06XVxzKj8pXC8oPyFbXC9cKl0pL2csJyQxPHIvJylbcl0oL1wvXCpbXHN8XFNdKj9cKlwvfFwvXC8uKnw8clwvLis/XC9cdyp8Ii4qPyJ8Jy4qPycvZyxmdW5jdGlvbihtKXtyZXR1cm4gInIiK3AucHVzaChtKSsiPiJ9KVtyXSgvKCgmW2xnXXQ7fFsmXC8rXC0qPT86Liw7KClcW1xde318JV4hXSkrKS9nLHMoJzE3YicpKVtyXSgvXGIoYnJlYWt8Y2FzZXxjYXRjaHxjb250aW51ZXxkZWZhdWx0fGRlbGV0ZXxkb3xlbHNlfGZhbHNlfGZpbmFsbHl8Zm9yfGZ1bmN0aW9ufGlmfGlufGluc3RhbmNlb2Z8bmV3fHJldHVybnxzd2l0Y2h8dGhpc3x0aHJvd3x0cnVlfHRyeXx0eXBlb2Z8dmFyfHZvaWR8d2hpbGV8d2l0aClcYi9naSxzKCdmMGInKSlbcl0oL1xiKDB4W1xkYS1mXSt8XGQrKVxiL2cscygnZDgzJykpW3JdKC9yKFxkKyk+L2csZnVuY3Rpb24obSxuKXtiPXBbbi0xXTtyZXR1cm4gYi5tYXRjaCgvXlwvW1wvKl0vKT9zKCc2NjYnLGIpOmIubWF0Y2goL15bIiddLyk/cygnNzE5JyxiKTpzKCc2YTAnLGIpfSlbcl0oLzxyL2csIiIpW3JdKC88cS9nLCJcXCciKVtyXSgvPGQvZywnXFwiJylbcl0oLzxsL2csJ1xcLycpW3JdKC88Yi9nLCdcXFxcJyl9aCgp

// This is just the highlighting function (no textarea, button, etc.)

function tinysh( code ) {
	var snippets = [];
	return code
	
		// html entities
		.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;').replace(/"/g,'&quot;')
	
		// tabs to 4 spaces
		.replace(/\t/g, '    ')
	
		// escaped backslashes, slashes, single quotes, double quotes
		.replace(/\\\\/g,'<ebs>').replace(/\\\//g,'<es>').replace(/\\'/g,'<esq>').replace(/\\"/g,'<edq>') 
		
		// regexp hint, so we can differentiate between 'replace(/foo/, bar);' and 'hours=seconds/60/60;'
		.replace(/([\[({=:]\s*?)\/(?![\/\*])/g, '$1<reh>/') 
	
		// comments, regexp, strings -> save in snippets array and replace with <r#> token
		.replace(/\/\*[\s|\S]*?\*\/|\/\/.*|<reh>\/.+?\/\w*|&quot;.*?&quot;|'.*?'/g, function( match ) { 
			return "<r" + snippets.push( match ) + ">"; 
		})
		
		// punctuations
		.replace(/(&lt;|&gt;|&amp;|[\/+\-*=?:.,;()\[\]{}|%^!])+/g, '<span class="punct">$&</span>')
		
		// keywords
		.replace(/\b(break|case|catch|continue|default|delete|do|else|false|finally|for|function|if|in|instanceof|new|return|switch|this|throw|true|try|typeof|var|void|while|with)\b/gi,
			'<span class="keyword">$1</span>'
		)
		
		// numbers (dec/hex)
		.replace(/\b(0x[\da-f]+|\d+)\b/g, '<span class="number">$1</span>')
		
		// paste snippets back in again
		.replace(/<r(\d+)>/g, function( match, id ) {
			var r = snippets[ id - 1 ];
			var css = r.match(/^(\/\/|\/\*|-)/) ? 'comment' : r.match(/^[&']/) ? 'string' : 'regexp';
			return '<span class="' + css + '">' + r + '</span>';
		})
		
		// strip all regexp hints
		.replace(/<reh>/g,"")
		
		// revert escaped characters
		.replace(/<esq>/g,"\\'").replace(/<edq>/g,'\\"').replace(/<es>/g,'\\/').replace(/<ebs>/g,'\\\\');
};