1// CodeMirror, copyright (c) by Marijn Haverbeke and others
 2// Distributed under an MIT license: https://codemirror.net/LICENSE
 3
 4// Utility function that allows modes to be combined. The mode given
 5// as the base argument takes care of most of the normal mode
 6// functionality, but a second (typically simple) mode is used, which
 7// can override the style of text. Both modes get to parse all of the
 8// text, but when both assign a non-null style to a piece of code, the
 9// overlay wins, unless the combine argument was true and not overridden,
10// or state.overlay.combineTokens was true, in which case the styles are
11// combined.
12
13(function(mod) {
14  if (typeof exports == "object" && typeof module == "object") // CommonJS
15    mod(require("../../lib/codemirror"));
16  else if (typeof define == "function" && define.amd) // AMD
17    define(["../../lib/codemirror"], mod);
18  else // Plain browser env
19    mod(CodeMirror);
20})(function(CodeMirror) {
21"use strict";
22
23CodeMirror.overlayMode = function(base, overlay, combine) {
24  return {
25    startState: function() {
26      return {
27        base: CodeMirror.startState(base),
28        overlay: CodeMirror.startState(overlay),
29        basePos: 0, baseCur: null,
30        overlayPos: 0, overlayCur: null,
31        streamSeen: null
32      };
33    },
34    copyState: function(state) {
35      return {
36        base: CodeMirror.copyState(base, state.base),
37        overlay: CodeMirror.copyState(overlay, state.overlay),
38        basePos: state.basePos, baseCur: null,
39        overlayPos: state.overlayPos, overlayCur: null
40      };
41    },
42
43    token: function(stream, state) {
44      if (stream != state.streamSeen ||
45          Math.min(state.basePos, state.overlayPos) < stream.start) {
46        state.streamSeen = stream;
47        state.basePos = state.overlayPos = stream.start;
48      }
49
50      if (stream.start == state.basePos) {
51        state.baseCur = base.token(stream, state.base);
52        state.basePos = stream.pos;
53      }
54      if (stream.start == state.overlayPos) {
55        stream.pos = stream.start;
56        state.overlayCur = overlay.token(stream, state.overlay);
57        state.overlayPos = stream.pos;
58      }
59      stream.pos = Math.min(state.basePos, state.overlayPos);
60
61      // state.overlay.combineTokens always takes precedence over combine,
62      // unless set to null
63      if (state.overlayCur == null) return state.baseCur;
64      else if (state.baseCur != null &&
65               state.overlay.combineTokens ||
66               combine && state.overlay.combineTokens == null)
67        return state.baseCur + " " + state.overlayCur;
68      else return state.overlayCur;
69    },
70
71    indent: base.indent && function(state, textAfter, line) {
72      return base.indent(state.base, textAfter, line);
73    },
74    electricChars: base.electricChars,
75
76    innerMode: function(state) { return {state: state.base, mode: base}; },
77
78    blankLine: function(state) {
79      var baseToken, overlayToken;
80      if (base.blankLine) baseToken = base.blankLine(state.base);
81      if (overlay.blankLine) overlayToken = overlay.blankLine(state.overlay);
82
83      return overlayToken == null ?
84        baseToken :
85        (combine && baseToken != null ? baseToken + " " + overlayToken : overlayToken);
86    }
87  };
88};
89
90});