squirrelly/src/regexps.js

Simple and powerful template engine that supports helpers, partials, filters, native code, and Express.

export var initialRegEx = /{{ *?(?:(?:(?:(?:([\w$]+ *?(?:[^\s\w($][^\n]*?)*?))|(?:@(?:([\w$]+:|(?:\.\.\/)+))? *(.+?) *))(?: *?(\| *?[\w$]+? *?)+?)?)|(?:([\w$]+) *?\(([^\n]*?)\) *?([\w$]*))|(?:\/ *?([\w$]+))|(?:# *?([\w$]+))|(?:([\w$]+) *?\(([^\n]*?)\) *?\/)|(?:!--[^]+?--)) *?}}\n?/g
export var initialTags = {
  s: '{{',
  e: '}}'
}

// The regExp below matches all helper references inside helper parameters
var paramHelperRefRegExp = /"(?:[^"\\]|\\.)*"|'(?:[^'\\]|\\.)*'|[\\]@(?:[\w$]*:)?[\w$]+|@(?:([\w$]*):)?([\w$]+)/g

export var regEx = initialRegEx
export var tags = initialTags

export function setup () { // Resets the current tags to the default tags
  tags = initialTags
  regEx = initialRegEx
  regEx.lastIndex = 0
}

export function defaultTags (tagArray) { // Redefine the default tags of the regexp
  changeTags(tagArray[0], tagArray[1])
  initialRegEx = regEx
  initialTags = tags
}

export function changeTags (firstTag, secondTag) { // Update current tags
  var newRegEx = firstTag + regEx.source.slice(tags.s.length, 0 - (tags.e.length + 3)) + secondTag + '\\n?'
  var lastIndex = regEx.lastIndex
  tags = {
    s: firstTag,
    e: secondTag
  }
  regEx = RegExp(newRegEx, 'g')
  regEx.lastIndex = lastIndex
}

export function replaceParamHelpers (params) {
  params = params.replace(paramHelperRefRegExp, function (m, p1, p2) { // p1 scope, p2 string
    if (typeof p2 === 'undefined') {
      return m
    } else {
      if (typeof p1 === 'undefined') {
        p1 = ''
      }
      return 'hvals' + p1 + '.' + p2
    }
  })
  return params
}

// The whole regular expression can be hard to comprehend, so here it's broken down.
// You can pass the string between "START REGEXP" and "END REGEXP" into a regular expression
// That removes whitespace and comments, and outputs a working regular expression.

/* START REGEXP
{{ *? //the beginning
(?: //or for each possible tag
(?: //if a global or helper ref
(?: //choosing global or helper ref
(?:([\w$]+ *?(?:[^\s\w($][^\n]*?)*?)) //global reference
|
(?:@(?:([\w$]+:|(?:\.\.\/)+))? *(.+?) *) //helper reference
)
(?: *?(\| *?[\w$]+? *?)+?)? //filter
) //end if a global or helper ref
| //now if a helper oTag
(?:([\w$]+) *?\(([^\n]*?)\) *?([\w$]*))
| //now if a helper cTag
(?:\/ *?([\w$]+))
| //now if a helper block
(?:# *?([\w$]+))
| //now for a self closing tag
(?:([\w$]+) *?\(([^\n]*?)\) *?\/)
| //now for comments
(?:!--[^]+?--)
) //end or for each possible tag
 *?}}
\n? //To replace a newline at the end of a line

END REGEXP */
/*
p1: global ref main
p2: helper ref id (with ':' after it) or path
p3: helper ref main
p4: filters
p5: helper name
p6: helper parameters
p7: helper id
p8: helper cTag name
p9: helper block name
p10: self closing helper name
p11: self closing helper params
Here's the RegExp I use to turn the expanded version between START REGEXP and END REGEXP to a working one: I replace [\f\n\r\t\v\u00a0\u1680\u2000\u200a\u2028\u2029\u202f\u205f\u3000\ufeff]| \/\/[\w ']+\n with nothing.
*/