ZhongMianAdmin/docs/libs/codemirror/mode/verilog/verilog.js

// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: https://codemirror.net/LICENSE

;(function (mod) {
    if (typeof exports == 'object' && typeof module == 'object')
        // CommonJS
        mod(require('../../lib/codemirror'))
    else if (typeof define == 'function' && define.amd)
        // AMD
        define(['../../lib/codemirror'], mod)
    // Plain browser env
    else mod(CodeMirror)
})(function (CodeMirror) {
    'use strict'

    CodeMirror.defineMode('verilog', function (config, parserConfig) {
        var indentUnit = config.indentUnit,
            statementIndentUnit = parserConfig.statementIndentUnit || indentUnit,
            dontAlignCalls = parserConfig.dontAlignCalls,
            // compilerDirectivesUseRegularIndentation - If set, Compiler directive
            // indentation follows the same rules as everything else. Otherwise if
            // false, compiler directives will track their own indentation.
            // For example, `ifdef nested inside another `ifndef will be indented,
            // but a `ifdef inside a function block may not be indented.
            compilerDirectivesUseRegularIndentation = parserConfig.compilerDirectivesUseRegularIndentation,
            noIndentKeywords = parserConfig.noIndentKeywords || [],
            multiLineStrings = parserConfig.multiLineStrings,
            hooks = parserConfig.hooks || {}

        function words(str) {
            var obj = {},
                words = str.split(' ')
            for (var i = 0; i < words.length; ++i) obj[words[i]] = true
            return obj
        }

        /**
         * Keywords from IEEE 1800-2012
         */
        var keywords = words(
            'accept_on alias always always_comb always_ff always_latch and assert assign assume automatic before begin bind ' +
                'bins binsof bit break buf bufif0 bufif1 byte case casex casez cell chandle checker class clocking cmos config ' +
                'const constraint context continue cover covergroup coverpoint cross deassign default defparam design disable ' +
                'dist do edge else end endcase endchecker endclass endclocking endconfig endfunction endgenerate endgroup ' +
                'endinterface endmodule endpackage endprimitive endprogram endproperty endspecify endsequence endtable endtask ' +
                'enum event eventually expect export extends extern final first_match for force foreach forever fork forkjoin ' +
                'function generate genvar global highz0 highz1 if iff ifnone ignore_bins illegal_bins implements implies import ' +
                'incdir include initial inout input inside instance int integer interconnect interface intersect join join_any ' +
                'join_none large let liblist library local localparam logic longint macromodule matches medium modport module ' +
                'nand negedge nettype new nexttime nmos nor noshowcancelled not notif0 notif1 null or output package packed ' +
                'parameter pmos posedge primitive priority program property protected pull0 pull1 pulldown pullup ' +
                'pulsestyle_ondetect pulsestyle_onevent pure rand randc randcase randsequence rcmos real realtime ref reg ' +
                'reject_on release repeat restrict return rnmos rpmos rtran rtranif0 rtranif1 s_always s_eventually s_nexttime ' +
                's_until s_until_with scalared sequence shortint shortreal showcancelled signed small soft solve specify ' +
                'specparam static string strong strong0 strong1 struct super supply0 supply1 sync_accept_on sync_reject_on ' +
                'table tagged task this throughout time timeprecision timeunit tran tranif0 tranif1 tri tri0 tri1 triand trior ' +
                'trireg type typedef union unique unique0 unsigned until until_with untyped use uwire var vectored virtual void ' +
                'wait wait_order wand weak weak0 weak1 while wildcard wire with within wor xnor xor'
        )

        /** Operators from IEEE 1800-2012
     unary_operator ::=
       + | - | ! | ~ | & | ~& | | | ~| | ^ | ~^ | ^~
     binary_operator ::=
       + | - | * | / | % | == | != | === | !== | ==? | !=? | && | || | **
       | < | <= | > | >= | & | | | ^ | ^~ | ~^ | >> | << | >>> | <<<
       | -> | <->
     inc_or_dec_operator ::= ++ | --
     unary_module_path_operator ::=
       ! | ~ | & | ~& | | | ~| | ^ | ~^ | ^~
     binary_module_path_operator ::=
       == | != | && | || | & | | | ^ | ^~ | ~^
  */
        var isOperatorChar = /[\+\-\*\/!~&|^%=?:<>]/
        var isBracketChar = /[\[\]{}()]/

        var unsignedNumber = /\d[0-9_]*/
        var decimalLiteral = /\d*\s*'s?d\s*\d[0-9_]*/i
        var binaryLiteral = /\d*\s*'s?b\s*[xz01][xz01_]*/i
        var octLiteral = /\d*\s*'s?o\s*[xz0-7][xz0-7_]*/i
        var hexLiteral = /\d*\s*'s?h\s*[0-9a-fxz?][0-9a-fxz?_]*/i
        var realLiteral = /(\d[\d_]*(\.\d[\d_]*)?E-?[\d_]+)|(\d[\d_]*\.\d[\d_]*)/i

        var closingBracketOrWord = /^((`?\w+)|[)}\]])/
        var closingBracket = /[)}\]]/
        var compilerDirectiveRegex = new RegExp(
            '^(`(?:ifdef|ifndef|elsif|else|endif|undef|undefineall|define|include|begin_keywords|celldefine|default|' +
                'nettype|end_keywords|endcelldefine|line|nounconnected_drive|pragma|resetall|timescale|unconnected_drive))\\b'
        )
        var compilerDirectiveBeginRegex = /^(`(?:ifdef|ifndef|elsif|else))\b/
        var compilerDirectiveEndRegex = /^(`(?:elsif|else|endif))\b/

        var curPunc
        var curKeyword

        // Block openings which are closed by a matching keyword in the form of ("end" + keyword)
        // E.g. "task" => "endtask"
        var blockKeywords = words('case checker class clocking config function generate interface module package ' + 'primitive program property specify sequence table task')

        // Opening/closing pairs
        var openClose = {}
        for (var keyword in blockKeywords) {
            openClose[keyword] = 'end' + keyword
        }
        openClose['begin'] = 'end'
        openClose['casex'] = 'endcase'
        openClose['casez'] = 'endcase'
        openClose['do'] = 'while'
        openClose['fork'] = 'join;join_any;join_none'
        openClose['covergroup'] = 'endgroup'
        openClose['macro_begin'] = 'macro_end'

        for (var i in noIndentKeywords) {
            var keyword = noIndentKeywords[i]
            if (openClose[keyword]) {
                openClose[keyword] = undefined
            }
        }

        // Keywords which open statements that are ended with a semi-colon
        var statementKeywords = words('always always_comb always_ff always_latch assert assign assume else export for foreach forever if import initial repeat while extern typedef')

        function tokenBase(stream, state) {
            var ch = stream.peek(),
                style
            if (hooks[ch] && (style = hooks[ch](stream, state)) != false) return style
            if (hooks.tokenBase && (style = hooks.tokenBase(stream, state)) != false) return style

            if (/[,;:\.]/.test(ch)) {
                curPunc = stream.next()
                return null
            }
            if (isBracketChar.test(ch)) {
                curPunc = stream.next()
                return 'bracket'
            }
            // Macros (tick-defines)
            if (ch == '`') {
                stream.next()
                if (stream.eatWhile(/[\w\$_]/)) {
                    var cur = stream.current()
                    curKeyword = cur
                    // Macros that end in _begin, are start of block and end with _end
                    if (cur.startsWith('`uvm_') && cur.endsWith('_begin')) {
                        var keywordClose = curKeyword.substr(0, curKeyword.length - 5) + 'end'
                        openClose[cur] = keywordClose
                        curPunc = 'newblock'
                    } else {
                        stream.eatSpace()
                        if (stream.peek() == '(') {
                            // Check if this is a block
                            curPunc = 'newmacro'
                        }
                        var withSpace = stream.current()
                        // Move the stream back before the spaces
                        stream.backUp(withSpace.length - cur.length)
                    }
                    return 'def'
                } else {
                    return null
                }
            }
            // System calls
            if (ch == '$') {
                stream.next()
                if (stream.eatWhile(/[\w\$_]/)) {
                    return 'meta'
                } else {
                    return null
                }
            }
            // Time literals
            if (ch == '#') {
                stream.next()
                stream.eatWhile(/[\d_.]/)
                return 'def'
            }
            // Event
            if (ch == '@') {
                stream.next()
                stream.eatWhile(/[@]/)
                return 'def'
            }
            // Strings
            if (ch == '"') {
                stream.next()
                state.tokenize = tokenString(ch)
                return state.tokenize(stream, state)
            }
            // Comments
            if (ch == '/') {
                stream.next()
                if (stream.eat('*')) {
                    state.tokenize = tokenComment
                    return tokenComment(stream, state)
                }
                if (stream.eat('/')) {
                    stream.skipToEnd()
                    return 'comment'
                }
                stream.backUp(1)
            }

            // Numeric literals
            if (
                stream.match(realLiteral) ||
                stream.match(decimalLiteral) ||
                stream.match(binaryLiteral) ||
                stream.match(octLiteral) ||
                stream.match(hexLiteral) ||
                stream.match(unsignedNumber) ||
                stream.match(realLiteral)
            ) {
                return 'number'
            }

            // Operators
            if (stream.eatWhile(isOperatorChar)) {
                curPunc = stream.current()
                return 'meta'
            }

            // Keywords / plain variables
            if (stream.eatWhile(/[\w\$_]/)) {
                var cur = stream.current()
                if (keywords[cur]) {
                    if (openClose[cur]) {
                        curPunc = 'newblock'
                        if (cur === 'fork') {
                            // Fork can be a statement instead of block in cases of:
                            // "disable fork;" and "wait fork;" (trailing semicolon)
                            stream.eatSpace()
                            if (stream.peek() == ';') {
                                curPunc = 'newstatement'
                            }
                            stream.backUp(stream.current().length - cur.length)
                        }
                    }
                    if (statementKeywords[cur]) {
                        curPunc = 'newstatement'
                    }
                    curKeyword = cur
                    return 'keyword'
                }
                return 'variable'
            }

            stream.next()
            return null
        }

        function tokenString(quote) {
            return function (stream, state) {
                var escaped = false,
                    next,
                    end = false
                while ((next = stream.next()) != null) {
                    if (next == quote && !escaped) {
                        end = true
                        break
                    }
                    escaped = !escaped && next == '\\'
                }
                if (end || !(escaped || multiLineStrings)) state.tokenize = tokenBase
                return 'string'
            }
        }

        function tokenComment(stream, state) {
            var maybeEnd = false,
                ch
            while ((ch = stream.next())) {
                if (ch == '/' && maybeEnd) {
                    state.tokenize = tokenBase
                    break
                }
                maybeEnd = ch == '*'
            }
            return 'comment'
        }

        function Context(indented, column, type, scopekind, align, prev) {
            this.indented = indented
            this.column = column
            this.type = type
            this.scopekind = scopekind
            this.align = align
            this.prev = prev
        }
        function pushContext(state, col, type, scopekind) {
            var indent = state.indented
            var c = new Context(indent, col, type, scopekind ? scopekind : '', null, state.context)
            return (state.context = c)
        }
        function popContext(state) {
            var t = state.context.type
            if (t == ')' || t == ']' || t == '}') {
                state.indented = state.context.indented
            }
            return (state.context = state.context.prev)
        }

        function isClosing(text, contextClosing) {
            if (text == contextClosing) {
                return true
            } else {
                // contextClosing may be multiple keywords separated by ;
                var closingKeywords = contextClosing.split(';')
                for (var i in closingKeywords) {
                    if (text == closingKeywords[i]) {
                        return true
                    }
                }
                return false
            }
        }

        function isInsideScopeKind(ctx, scopekind) {
            if (ctx == null) {
                return false
            }
            if (ctx.scopekind === scopekind) {
                return true
            }
            return isInsideScopeKind(ctx.prev, scopekind)
        }

        function buildElectricInputRegEx() {
            // Reindentation should occur on any bracket char: {}()[]
            // or on a match of any of the block closing keywords, at
            // the end of a line
            var allClosings = []
            for (var i in openClose) {
                if (openClose[i]) {
                    var closings = openClose[i].split(';')
                    for (var j in closings) {
                        allClosings.push(closings[j])
                    }
                }
            }
            var re = new RegExp('[{}()\\[\\]]|(' + allClosings.join('|') + ')$')
            return re
        }

        // Interface
        return {
            // Regex to force current line to reindent
            electricInput: buildElectricInputRegEx(),

            startState: function (basecolumn) {
                var state = {
                    tokenize: null,
                    context: new Context((basecolumn || 0) - indentUnit, 0, 'top', 'top', false),
                    indented: 0,
                    compilerDirectiveIndented: 0,
                    startOfLine: true,
                }
                if (hooks.startState) hooks.startState(state)
                return state
            },

            token: function (stream, state) {
                var ctx = state.context
                if (stream.sol()) {
                    if (ctx.align == null) ctx.align = false
                    state.indented = stream.indentation()
                    state.startOfLine = true
                }
                if (hooks.token) {
                    // Call hook, with an optional return value of a style to override verilog styling.
                    var style = hooks.token(stream, state)
                    if (style !== undefined) {
                        return style
                    }
                }
                if (stream.eatSpace()) return null
                curPunc = null
                curKeyword = null
                var style = (state.tokenize || tokenBase)(stream, state)
                if (style == 'comment' || style == 'meta' || style == 'variable') {
                    if ((curPunc === '=' || curPunc === '<=') && !isInsideScopeKind(ctx, 'assignment')) {
                        // '<=' could be nonblocking assignment or lessthan-equals (which shouldn't cause indent)
                        //      Search through the context to see if we are already in an assignment.
                        // '=' could be inside port declaration with comma or ')' afterward, or inside for(;;) block.
                        pushContext(state, stream.column() + curPunc.length, 'assignment', 'assignment')
                        if (ctx.align == null) ctx.align = true
                    }
                    return style
                }
                if (ctx.align == null) ctx.align = true

                var isClosingAssignment = ctx.type == 'assignment' && closingBracket.test(curPunc) && ctx.prev && ctx.prev.type === curPunc
                if (curPunc == ctx.type || isClosingAssignment) {
                    if (isClosingAssignment) {
                        ctx = popContext(state)
                    }
                    ctx = popContext(state)
                    if (curPunc == ')') {
                        // Handle closing macros, assuming they could have a semicolon or begin/end block inside.
                        if (ctx && ctx.type === 'macro') {
                            ctx = popContext(state)
                            while (ctx && (ctx.type == 'statement' || ctx.type == 'assignment')) ctx = popContext(state)
                        }
                    } else if (curPunc == '}') {
                        // Handle closing statements like constraint block: "foreach () {}" which
                        // do not have semicolon at end.
                        if (ctx && ctx.type === 'statement') {
                            while (ctx && ctx.type == 'statement') ctx = popContext(state)
                        }
                    }
                } else if (((curPunc == ';' || curPunc == ',') && (ctx.type == 'statement' || ctx.type == 'assignment')) || (ctx.type && isClosing(curKeyword, ctx.type))) {
                    ctx = popContext(state)
                    while (ctx && (ctx.type == 'statement' || ctx.type == 'assignment')) ctx = popContext(state)
                } else if (curPunc == '{') {
                    pushContext(state, stream.column(), '}')
                } else if (curPunc == '[') {
                    pushContext(state, stream.column(), ']')
                } else if (curPunc == '(') {
                    pushContext(state, stream.column(), ')')
                } else if (ctx && ctx.type == 'endcase' && curPunc == ':') {
                    pushContext(state, stream.column(), 'statement', 'case')
                } else if (curPunc == 'newstatement') {
                    pushContext(state, stream.column(), 'statement', curKeyword)
                } else if (curPunc == 'newblock') {
                    if (curKeyword == 'function' && ctx && (ctx.type == 'statement' || ctx.type == 'endgroup')) {
                        // The 'function' keyword can appear in some other contexts where it actually does not
                        // indicate a function (import/export DPI and covergroup definitions).
                        // Do nothing in this case
                    } else if (curKeyword == 'task' && ctx && ctx.type == 'statement') {
                        // Same thing for task
                    } else if (curKeyword == 'class' && ctx && ctx.type == 'statement') {
                        // Same thing for class (e.g. typedef)
                    } else {
                        var close = openClose[curKeyword]
                        pushContext(state, stream.column(), close, curKeyword)
                    }
                } else if (curPunc == 'newmacro' || (curKeyword && curKeyword.match(compilerDirectiveRegex))) {
                    if (curPunc == 'newmacro') {
                        // Macros (especially if they have parenthesis) potentially have a semicolon
                        // or complete statement/block inside, and should be treated as such.
                        pushContext(state, stream.column(), 'macro', 'macro')
                    }
                    if (curKeyword.match(compilerDirectiveEndRegex)) {
                        state.compilerDirectiveIndented -= statementIndentUnit
                    }
                    if (curKeyword.match(compilerDirectiveBeginRegex)) {
                        state.compilerDirectiveIndented += statementIndentUnit
                    }
                }

                state.startOfLine = false
                return style
            },

            indent: function (state, textAfter) {
                if (state.tokenize != tokenBase && state.tokenize != null) return CodeMirror.Pass
                if (hooks.indent) {
                    var fromHook = hooks.indent(state)
                    if (fromHook >= 0) return fromHook
                }
                var ctx = state.context,
                    firstChar = textAfter && textAfter.charAt(0)
                if (ctx.type == 'statement' && firstChar == '}') ctx = ctx.prev
                var closing = false
                var possibleClosing = textAfter.match(closingBracketOrWord)
                if (possibleClosing) closing = isClosing(possibleClosing[0], ctx.type)
                if (!compilerDirectivesUseRegularIndentation && textAfter.match(compilerDirectiveRegex)) {
                    if (textAfter.match(compilerDirectiveEndRegex)) {
                        return state.compilerDirectiveIndented - statementIndentUnit
                    }
                    return state.compilerDirectiveIndented
                }
                if (ctx.type == 'statement') return ctx.indented + (firstChar == '{' ? 0 : statementIndentUnit)
                else if ((closingBracket.test(ctx.type) || ctx.type == 'assignment') && ctx.align && !dontAlignCalls) return ctx.column + (closing ? 0 : 1)
                else if (ctx.type == ')' && !closing) return ctx.indented + statementIndentUnit
                else return ctx.indented + (closing ? 0 : indentUnit)
            },

            blockCommentStart: '/*',
            blockCommentEnd: '*/',
            lineComment: '//',
            fold: 'indent',
        }
    })

    CodeMirror.defineMIME('text/x-verilog', {
        name: 'verilog',
    })

    CodeMirror.defineMIME('text/x-systemverilog', {
        name: 'verilog',
    })

    // TL-Verilog mode.
    // See tl-x.org for language spec.
    // See the mode in action at makerchip.com.
    // Contact: steve.hoover@redwoodeda.com

    // TLV Identifier prefixes.
    // Note that sign is not treated separately, so "+/-" versions of numeric identifiers
    // are included.
    var tlvIdentifierStyle = {
        '|': 'link',
        '>': 'property', // Should condition this off for > TLV 1c.
        $: 'variable',
        $$: 'variable',
        '?$': 'qualifier',
        '?*': 'qualifier',
        '-': 'hr',
        '/': 'property',
        '/-': 'property',
        '@': 'variable-3',
        '@-': 'variable-3',
        '@++': 'variable-3',
        '@+=': 'variable-3',
        '@+=-': 'variable-3',
        '@--': 'variable-3',
        '@-=': 'variable-3',
        '%+': 'tag',
        '%-': 'tag',
        '%': 'tag',
        '>>': 'tag',
        '<<': 'tag',
        '<>': 'tag',
        '#': 'tag', // Need to choose a style for this.
        '^': 'attribute',
        '^^': 'attribute',
        '^!': 'attribute',
        '*': 'variable-2',
        '**': 'variable-2',
        '\\': 'keyword',
        '"': 'comment',
    }

    // Lines starting with these characters define scope (result in indentation).
    var tlvScopePrefixChars = {
        '/': 'beh-hier',
        '>': 'beh-hier',
        '-': 'phys-hier',
        '|': 'pipe',
        '?': 'when',
        '@': 'stage',
        '\\': 'keyword',
    }
    var tlvIndentUnit = 3
    var tlvTrackStatements = false
    var tlvIdentMatch = /^([~!@#\$%\^&\*-\+=\?\/\\\|'"<>]+)([\d\w_]*)/ // Matches an identifier.
    // Note that ':' is excluded, because of it's use in [:].
    var tlvFirstLevelIndentMatch = /^[! ]  /
    var tlvLineIndentationMatch = /^[! ] */
    var tlvCommentMatch = /^\/[\/\*]/

    // Returns a style specific to the scope at the given indentation column.
    // Type is one of: "indent", "scope-ident", "before-scope-ident".
    function tlvScopeStyle(state, indentation, type) {
        // Begin scope.
        var depth = indentation / tlvIndentUnit // TODO: Pass this in instead.
        return 'tlv-' + state.tlvIndentationStyle[depth] + '-' + type
    }

    // Return true if the next thing in the stream is an identifier with a mnemonic.
    function tlvIdentNext(stream) {
        var match
        return (match = stream.match(tlvIdentMatch, false)) && match[2].length > 0
    }

    CodeMirror.defineMIME('text/x-tlv', {
        name: 'verilog',

        hooks: {
            electricInput: false,

            // Return undefined for verilog tokenizing, or style for TLV token (null not used).
            // Standard CM styles are used for most formatting, but some TL-Verilog-specific highlighting
            // can be enabled with the definition of cm-tlv-* styles, including highlighting for:
            //   - M4 tokens
            //   - TLV scope indentation
            //   - Statement delimitation (enabled by tlvTrackStatements)
            token: function (stream, state) {
                var style = undefined
                var match // Return value of pattern matches.

                // Set highlighting mode based on code region (TLV or SV).
                if (stream.sol() && !state.tlvInBlockComment) {
                    // Process region.
                    if (stream.peek() == '\\') {
                        style = 'def'
                        stream.skipToEnd()
                        if (stream.string.match(/\\SV/)) {
                            state.tlvCodeActive = false
                        } else if (stream.string.match(/\\TLV/)) {
                            state.tlvCodeActive = true
                        }
                    }
                    // Correct indentation in the face of a line prefix char.
                    if (state.tlvCodeActive && stream.pos == 0 && state.indented == 0 && (match = stream.match(tlvLineIndentationMatch, false))) {
                        state.indented = match[0].length
                    }

                    // Compute indentation state:
                    //   o Auto indentation on next line
                    //   o Indentation scope styles
                    var indented = state.indented
                    var depth = indented / tlvIndentUnit
                    if (depth <= state.tlvIndentationStyle.length) {
                        // not deeper than current scope

                        var blankline = stream.string.length == indented
                        var chPos = depth * tlvIndentUnit
                        if (chPos < stream.string.length) {
                            var bodyString = stream.string.slice(chPos)
                            var ch = bodyString[0]
                            if (tlvScopePrefixChars[ch] && (match = bodyString.match(tlvIdentMatch)) && tlvIdentifierStyle[match[1]]) {
                                // This line begins scope.
                                // Next line gets indented one level.
                                indented += tlvIndentUnit
                                // Style the next level of indentation (except non-region keyword identifiers,
                                //   which are statements themselves)
                                if (!(ch == '\\' && chPos > 0)) {
                                    state.tlvIndentationStyle[depth] = tlvScopePrefixChars[ch]
                                    if (tlvTrackStatements) {
                                        state.statementComment = false
                                    }
                                    depth++
                                }
                            }
                        }
                        // Clear out deeper indentation levels unless line is blank.
                        if (!blankline) {
                            while (state.tlvIndentationStyle.length > depth) {
                                state.tlvIndentationStyle.pop()
                            }
                        }
                    }
                    // Set next level of indentation.
                    state.tlvNextIndent = indented
                }

                if (state.tlvCodeActive) {
                    // Highlight as TLV.

                    var beginStatement = false
                    if (tlvTrackStatements) {
                        // This starts a statement if the position is at the scope level
                        // and we're not within a statement leading comment.
                        beginStatement =
                            stream.peek() != ' ' && // not a space
                            style === undefined && // not a region identifier
                            !state.tlvInBlockComment && // not in block comment
                            //!stream.match(tlvCommentMatch, false) && // not comment start
                            stream.column() == state.tlvIndentationStyle.length * tlvIndentUnit // at scope level
                        if (beginStatement) {
                            if (state.statementComment) {
                                // statement already started by comment
                                beginStatement = false
                            }
                            state.statementComment = stream.match(tlvCommentMatch, false) // comment start
                        }
                    }

                    var match
                    if (style !== undefined) {
                        // Region line.
                        style += ' ' + tlvScopeStyle(state, 0, 'scope-ident')
                    } else if (stream.pos / tlvIndentUnit < state.tlvIndentationStyle.length && (match = stream.match(stream.sol() ? tlvFirstLevelIndentMatch : /^   /))) {
                        // Indentation
                        style = // make this style distinct from the previous one to prevent
                            // codemirror from combining spans
                            'tlv-indent-' +
                            (stream.pos % 2 == 0 ? 'even' : 'odd') +
                            // and style it
                            ' ' +
                            tlvScopeStyle(state, stream.pos - tlvIndentUnit, 'indent')
                        // Style the line prefix character.
                        if (match[0].charAt(0) == '!') {
                            style += ' tlv-alert-line-prefix'
                        }
                        // Place a class before a scope identifier.
                        if (tlvIdentNext(stream)) {
                            style += ' ' + tlvScopeStyle(state, stream.pos, 'before-scope-ident')
                        }
                    } else if (state.tlvInBlockComment) {
                        // In a block comment.
                        if (stream.match(/^.*?\*\//)) {
                            // Exit block comment.
                            state.tlvInBlockComment = false
                            if (tlvTrackStatements && !stream.eol()) {
                                // Anything after comment is assumed to be real statement content.
                                state.statementComment = false
                            }
                        } else {
                            stream.skipToEnd()
                        }
                        style = 'comment'
                    } else if ((match = stream.match(tlvCommentMatch)) && !state.tlvInBlockComment) {
                        // Start comment.
                        if (match[0] == '//') {
                            // Line comment.
                            stream.skipToEnd()
                        } else {
                            // Block comment.
                            state.tlvInBlockComment = true
                        }
                        style = 'comment'
                    } else if ((match = stream.match(tlvIdentMatch))) {
                        // looks like an identifier (or identifier prefix)
                        var prefix = match[1]
                        var mnemonic = match[2]
                        if (
                            // is identifier prefix
                            tlvIdentifierStyle.hasOwnProperty(prefix) &&
                            // has mnemonic or we're at the end of the line (maybe it hasn't been typed yet)
                            (mnemonic.length > 0 || stream.eol())
                        ) {
                            style = tlvIdentifierStyle[prefix]
                            if (stream.column() == state.indented) {
                                // Begin scope.
                                style += ' ' + tlvScopeStyle(state, stream.column(), 'scope-ident')
                            }
                        } else {
                            // Just swallow one character and try again.
                            // This enables subsequent identifier match with preceding symbol character, which
                            //   is legal within a statement.  (E.g., !$reset).  It also enables detection of
                            //   comment start with preceding symbols.
                            stream.backUp(stream.current().length - 1)
                            style = 'tlv-default'
                        }
                    } else if (stream.match(/^\t+/)) {
                        // Highlight tabs, which are illegal.
                        style = 'tlv-tab'
                    } else if (stream.match(/^[\[\]{}\(\);\:]+/)) {
                        // [:], (), {}, ;.
                        style = 'meta'
                    } else if ((match = stream.match(/^[mM]4([\+_])?[\w\d_]*/))) {
                        // m4 pre proc
                        style = match[1] == '+' ? 'tlv-m4-plus' : 'tlv-m4'
                    } else if (stream.match(/^ +/)) {
                        // Skip over spaces.
                        if (stream.eol()) {
                            // Trailing spaces.
                            style = 'error'
                        } else {
                            // Non-trailing spaces.
                            style = 'tlv-default'
                        }
                    } else if (stream.match(/^[\w\d_]+/)) {
                        // alpha-numeric token.
                        style = 'number'
                    } else {
                        // Eat the next char w/ no formatting.
                        stream.next()
                        style = 'tlv-default'
                    }
                    if (beginStatement) {
                        style += ' tlv-statement'
                    }
                } else {
                    if (stream.match(/^[mM]4([\w\d_]*)/)) {
                        // m4 pre proc
                        style = 'tlv-m4'
                    }
                }
                return style
            },

            indent: function (state) {
                return state.tlvCodeActive == true ? state.tlvNextIndent : -1
            },

            startState: function (state) {
                state.tlvIndentationStyle = [] // Styles to use for each level of indentation.
                state.tlvCodeActive = true // True when we're in a TLV region (and at beginning of file).
                state.tlvNextIndent = -1 // The number of spaces to autoindent the next line if tlvCodeActive.
                state.tlvInBlockComment = false // True inside /**/ comment.
                if (tlvTrackStatements) {
                    state.statementComment = false // True inside a statement's header comment.
                }
            },
        },
    })
})