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Prototype for conversion to CSTParser.EXPR
This demonstrates the basic approach working, but various things don't work here yet due to at least two things: * Mismatch between the way the two packages tokenize the input, eg, for the delimiters in strings. * Missing "trivia nodes" in JuliaSyntax (eg, a brackets node). These should probably be added.
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‎prototypes/cst_conversion.jl‎

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# A prototype for converting JuliaSyntax data structures into CSTParser.EXPR.
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using CSTParser
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using JuliaSyntax
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using JuliaSyntax: GreenNode, SyntaxHead, SourceFile, TaggedRange,
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@K_str, @KSet_cmd,
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haschildren, is_syntax_kind, is_keyword, is_operator, is_identifier, head, kind, span,
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is_infix, is_trivia, untokenize, TzTokens, children
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# See CSTParser.tokenkindtoheadmap
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function tokenkindtoheadmap(k::TzTokens.Kind)
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k === TzTokens.COMMA ? :COMMA :
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k === TzTokens.LPAREN ? :LPAREN :
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k === TzTokens.RPAREN ? :RPAREN :
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k === TzTokens.LSQUARE ? :LSQUARE :
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k === TzTokens.RSQUARE ? :RSQUARE :
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k === TzTokens.LBRACE ? :LBRACE :
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k === TzTokens.RBRACE ? :RBRACE :
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k === TzTokens.AT_SIGN ? :ATSIGN :
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k === TzTokens.DOT ? :DOT :
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k === TzTokens.ABSTRACT ? :ABSTRACT :
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k === TzTokens.BAREMODULE ? :BAREMODULE :
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k === TzTokens.BEGIN ? :BEGIN :
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k === TzTokens.BREAK ? :BREAK :
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k === TzTokens.CATCH ? :CATCH :
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k === TzTokens.CONST ? :CONST :
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k === TzTokens.CONTINUE ? :CONTINUE :
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k === TzTokens.DO ? :DO :
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k === TzTokens.ELSE ? :ELSE :
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k === TzTokens.ELSEIF ? :ELSEIF :
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k === TzTokens.END ? :END :
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k === TzTokens.EXPORT ? :EXPORT :
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k === TzTokens.FINALLY ? :FINALLY :
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k === TzTokens.FOR ? :FOR :
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k === TzTokens.FUNCTION ? :FUNCTION :
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k === TzTokens.GLOBAL ? :GLOBAL :
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k === TzTokens.IF ? :IF :
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k === TzTokens.IMPORT ? :IMPORT :
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k === TzTokens.LET ? :LET :
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k === TzTokens.LOCAL ? :LOCAL :
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k === TzTokens.MACRO ? :MACRO :
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k === TzTokens.MODULE ? :MODULE :
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k === TzTokens.MUTABLE ? :MUTABLE :
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k === TzTokens.OUTER ? :OUTER :
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k === TzTokens.PRIMITIVE ? :PRIMITIVE :
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k === TzTokens.QUOTE ? :QUOTE :
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k === TzTokens.RETURN ? :RETURN :
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k === TzTokens.STRUCT ? :STRUCT :
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k === TzTokens.TRY ? :TRY :
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k === TzTokens.TYPE ? :TYPE :
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k === TzTokens.USING ? :USING :
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k === TzTokens.WHILE ? :WHILE :
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k === TzTokens.INTEGER ? :INTEGER :
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k === TzTokens.BIN_INT ? :BININT :
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k === TzTokens.HEX_INT ? :HEXINT :
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k === TzTokens.OCT_INT ? :OCTINT :
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k === TzTokens.FLOAT ? :FLOAT :
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k === TzTokens.STRING ? :STRING :
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# k === TzTokens.TRIPLE_STRING ? :TRIPLESTRING :
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k === TzTokens.CHAR ? :CHAR :
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k === TzTokens.CMD ? :CMD :
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# k === TzTokens.TRIPLE_CMD ? :TRIPLECMD :
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k === TzTokens.TRUE ? :TRUE :
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k === TzTokens.FALSE ? :FALSE :
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k === TzTokens.ENDMARKER ? :errortoken :
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error("Unknown token $k")
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end
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# Things which are "trailing trivia" according to CSTParser
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#
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# "Trailing trivia" is trivia which will be attached to the end of a node.
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is_cst_trailing_trivia(x) = kind(x) in KSet`Whitespace NewlineWs Comment ;`
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# Convert GreenNode into CSTParser.EXPR
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function cst(source::SourceFile, raw_node::GreenNode{SyntaxHead}, position::Integer=1)
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node_start = position
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cs = children(raw_node)
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i = 1
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args = CSTParser.EXPR[]
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trivia = CSTParser.EXPR[]
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last_trivia_span = 0
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while i <= length(cs)
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raw = cs[i]
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if haschildren(raw)
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c = cst(source, raw, position)
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push!(args, c)
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last_trivia_span = c.fullspan - c.span
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position += span(raw)
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else
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start_pos = position
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token_start = i
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inner_span = span(raw)
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position += span(raw)
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# Here we append any trailing trivia tokens to the node.
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while i < length(cs) && is_cst_trailing_trivia(cs[i+1])
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position += span(cs[i+1])
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i += 1
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end
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full_span = position - start_pos
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last_trivia_span = full_span - inner_span
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# Leaf node
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k = kind(raw)
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val_range = start_pos:(start_pos + inner_span - 1)
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val = source[val_range]
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if kind(raw) == K"nothing"
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# First `nothing` token in file seems to require this. Why I don't know.
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inner_span = full_span
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end
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# See CSTParser.literalmap. Which we can't use directly because we've
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# customized Tokenize.jl :-(
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cst_head = k === TzTokens.NOTHING ? :NOTHING :
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# FIXME: Following probably need special handling
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k === TzTokens.MACRO_NAME ? :IDENTIFIER :
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k === TzTokens.CMD_MACRO_NAME ? :IDENTIFIER :
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k === TzTokens.STRING_MACRO_NAME ? :IDENTIFIER :
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k === TzTokens.DQUOTE ? :DQUOTE :
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k === TzTokens.BACKTICK ? :BACKTICK :
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is_operator(k) ? :OPERATOR :
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is_identifier(k) ? :IDENTIFIER :
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tokenkindtoheadmap(k)
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# FIXME: STRING, TRIPLE_STRING, CMD, TRIPLE_CMD, need special handling:
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# * STRING doesn't incude delimiters (DQUOTE tokens)
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# * CMD doesn't include delimiters (BACKTICK tokens)
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# * TRIPLE_STRING is a composite of STRING and TRIPLE_DQUOTE
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# * TRIPLE_CMD is a composite of CMD and TRIPLE_BACKTICK
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# They don't exist anymore as individual tokens
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push!(is_trivia(raw) ? trivia : args,
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CSTParser.EXPR(cst_head, nothing, nothing, full_span, inner_span, val,
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nothing, nothing))
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end
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i += 1
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end
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if is_infix(raw_node)
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args[1], args[2] = args[2], args[1]
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# TODO: Other argument swizzling, as done in SyntaxNode -> Expr conversions
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end
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full_span = position - node_start
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inner_span = full_span - last_trivia_span
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k = kind(raw_node)
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cst_head = k == K"toplevel" ? :file :
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is_operator(k) ? popfirst!(trivia) :
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Symbol(lowercase(string(kind(raw_node))))
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x = CSTParser.EXPR(cst_head, args,
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isempty(trivia) ? nothing : trivia,
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full_span, inner_span, nothing, nothing, nothing)
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for a in args
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a.parent = x
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end
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for a in trivia
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a.parent = x
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end
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return x
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end
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# Some steps of conversion to CSTParser.EXPR is most conveniently done on the
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# raw ParseStream representation. In particular, CSTParser.EXPR attaches
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# some types of trivia to the end of nontrivia or trivia tokens.
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#
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# This function reassociates trivia with nonterminal nodes to make converting
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# to CSTParser.EXPR a *local* operation on green tree nodes.
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function parse_for_cst(text)
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stream = JuliaSyntax.ParseStream(text)
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# Insert initial nothing node if necessary to anchor trailing whitespace.
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if is_cst_trailing_trivia(peek(stream, skip_whitespace=false))
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JuliaSyntax.bump_invisible(stream, K"nothing")
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end
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JuliaSyntax.parse(stream, rule=:toplevel)
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# Fix up start of stream
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ranges = stream.ranges
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@assert kind(ranges[end]) == K"toplevel"
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ranges[end] = let r = ranges[end]
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TaggedRange(r.head, 1, r.last_token)
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end
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# Rearrange whitespace trivia tokens so that they're always *trailing*
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# siblings of non-whitespace trivia tokens.
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#
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# This is required for later conversion to CSTParser.EXPR
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tokens = stream.tokens
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for (i,range) in enumerate(ranges)
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first_token = range.first_token
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while first_token < length(tokens) &&
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is_cst_trailing_trivia(tokens[first_token])
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first_token += 1
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end
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last_token = range.last_token
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while last_token < length(tokens) &&
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is_cst_trailing_trivia(tokens[last_token+1])
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last_token += 1
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end
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ranges[i] = TaggedRange(head(range), first_token, last_token)
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end
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return JuliaSyntax.build_tree(JuliaSyntax.GreenNode, stream)
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end
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# CSTParser.EXPR equality; should be in CSTParser...
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function Base.:(==)(x::CSTParser.EXPR, y::CSTParser.EXPR)
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# Debugging hacks:
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if x.head != y.head
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@info "Trivia mismatch" x.head y.head
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end
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if x.trivia != y.trivia
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@info "Trivia mismatch" x.trivia y.trivia
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end
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if x.fullspan != y.fullspan
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@info "Fullspan mismatch" x y x.fullspan y.fullspan
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end
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if x.span != y.span
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@info "Span mismatch" x y x.span y.span
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end
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if x.val != y.val
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@info "Trivia mismatch" x.val y.val
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end
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return x.head == y.head &&
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x.args == y.args &&
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x.trivia == y.trivia &&
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x.fullspan == y.fullspan &&
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x.span == y.span &&
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x.val == y.val &&
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x.meta == y.meta
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end
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# Some things which work
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#text = " 1 + 2 * 3 "
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#text = "[ 1 ; 2 ;]"
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#text = "for i=1:10\nx\ny\nend"
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#text = "100.00"
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text = """
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function f(x,y)
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s = 0
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for i = 1:10
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s += x - i^y
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end
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end
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"""
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# Some things which don't yet work
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#
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# Macro names
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# text = "@A.asdf x y"
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#
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# Bracket nodes don't exist yet in JuliaSyntax
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# text = "(a + b)"
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#
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# Strings have separate delimiters. Will need to put them back together.
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# text = "\"str\""
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source = SourceFile(text)
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ex = parse_for_cst(text)
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# show(stdout, MIME"text/plain"(), ex, text)
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y = CSTParser.parse(text, true)
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x = cst(source, ex)
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x == y
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