diff options
Diffstat (limited to 'compiler/parser.nim')
| -rw-r--r-- | compiler/parser.nim | 58 |
1 files changed, 52 insertions, 6 deletions
diff --git a/compiler/parser.nim b/compiler/parser.nim index 272c1b15f..d34a6d88a 100644 --- a/compiler/parser.nim +++ b/compiler/parser.nim @@ -33,6 +33,7 @@ type currInd: int # current indentation level firstTok, strongSpaces: bool # Has the first token been read? # Is strongSpaces on? + hasProgress: bool # some while loop requires progress ensurance lex*: TLexer # The lexer that is used for parsing tok*: TToken # The current token inPragma*: int # Pragma level @@ -71,6 +72,7 @@ proc getTok(p: var TParser) = ## Get the next token from the parser's lexer, and store it in the parser's ## `tok` member. rawGetTok(p.lex, p.tok) + p.hasProgress = true proc openParser*(p: var TParser, fileIdx: int32, inputStream: PLLStream, cache: IdentCache; @@ -310,6 +312,7 @@ proc parseSymbol(p: var TParser, allowNil = false): PNode = of tkAccent: result = newNodeP(nkAccQuoted, p) getTok(p) + # progress guaranteed while true: case p.tok.tokType of tkAccent: @@ -339,7 +342,7 @@ proc parseSymbol(p: var TParser, allowNil = false): PNode = # BUGFIX: We must consume a token here to prevent endless loops! # But: this really sucks for idetools and keywords, so we don't do it # if it is a keyword: - if not isKeyword(p.tok.tokType): getTok(p) + #if not isKeyword(p.tok.tokType): getTok(p) result = ast.emptyNode proc colonOrEquals(p: var TParser, a: PNode): PNode = @@ -367,6 +370,7 @@ proc exprList(p: var TParser, endTok: TTokType, result: PNode) = #| exprList = expr ^+ comma getTok(p) optInd(p, result) + # progress guaranteed while (p.tok.tokType != endTok) and (p.tok.tokType != tkEof): var a = parseExpr(p) addSon(result, a) @@ -392,6 +396,7 @@ proc exprColonEqExprListAux(p: var TParser, endTok: TTokType, result: PNode) = assert(endTok in {tkCurlyRi, tkCurlyDotRi, tkBracketRi, tkParRi}) getTok(p) optInd(p, result) + # progress guaranteed while p.tok.tokType != endTok and p.tok.tokType != tkEof: var a = exprColonEqExpr(p) addSon(result, a) @@ -416,6 +421,7 @@ proc setOrTableConstr(p: var TParser): PNode = getTok(p) # skip ':' result.kind = nkTableConstr else: + # progress guaranteed while p.tok.tokType notin {tkCurlyRi, tkEof}: var a = exprColonEqExpr(p) if a.kind == nkExprColonExpr: result.kind = nkTableConstr @@ -472,6 +478,7 @@ proc simpleExpr(p: var TParser, mode = pmNormal): PNode proc semiStmtList(p: var TParser, result: PNode) = inc p.inSemiStmtList result.add(complexOrSimpleStmt(p)) + # progress guaranteed while p.tok.tokType == tkSemiColon: getTok(p) optInd(p, result) @@ -533,6 +540,7 @@ proc parsePar(p: var TParser): PNode = if p.tok.tokType == tkComma: getTok(p) skipComment(p, a) + # progress guaranteed while p.tok.tokType != tkParRi and p.tok.tokType != tkEof: var a = exprColonEqExpr(p) addSon(result, a) @@ -657,6 +665,7 @@ proc namedParams(p: var TParser, callee: PNode, let a = callee result = newNodeP(kind, p) addSon(result, a) + # progress guaranteed exprColonEqExprListAux(p, endTok, result) proc parseMacroColon(p: var TParser, x: PNode): PNode @@ -676,10 +685,12 @@ proc primarySuffix(p: var TParser, r: PNode, baseIndent: int): PNode = else: parMessage(p, warnDeprecated, "a [b] will be parsed as command syntax; spacing") + # progress guaranteed while p.tok.indent < 0 or (p.tok.tokType == tkDot and p.tok.indent >= baseIndent): case p.tok.tokType of tkParLe: + # progress guaranteed somePar() result = namedParams(p, result, nkCall, tkParRi) if result.len > 1 and result.sons[1].kind == nkExprColonExpr: @@ -687,17 +698,21 @@ proc primarySuffix(p: var TParser, r: PNode, baseIndent: int): PNode = else: parseDoBlocks(p, result) of tkDo: + # progress guaranteed var a = result result = newNodeP(nkCall, p) addSon(result, a) parseDoBlocks(p, result) of tkDot: + # progress guaranteed result = dotExpr(p, result) result = parseGStrLit(p, result) of tkBracketLe: + # progress guaranteed somePar() result = namedParams(p, result, nkBracketExpr, tkBracketRi) of tkCurlyLe: + # progress guaranteed somePar() result = namedParams(p, result, nkCurlyExpr, tkCurlyRi) of tkSymbol, tkAccent, tkIntLit..tkCharLit, tkNil, tkCast, tkAddr, tkType: @@ -708,7 +723,10 @@ proc primarySuffix(p: var TParser, r: PNode, baseIndent: int): PNode = result = newNodeP(nkCommand, p) addSon(result, a) when true: + # progress NOT guaranteed + p.hasProgress = false addSon result, parseExpr(p) + if not p.hasProgress: break else: while p.tok.tokType != tkEof: let x = parseExpr(p) @@ -734,6 +752,7 @@ proc parseOperators(p: var TParser, headNode: PNode, var opPrec = getPrecedence(p.tok, p.strongSpaces) let modeB = if mode == pmTypeDef: pmTypeDesc else: mode # the operator itself must not start on a new line: + # progress guaranteed while opPrec >= limit and p.tok.indent < 0 and not isUnary(p): checkBinary(p) var leftAssoc = 1-ord(isRightAssociative(p.tok)) @@ -785,7 +804,9 @@ proc parsePragma(p: var TParser): PNode = getTok(p) optInd(p, result) while p.tok.tokType notin {tkCurlyDotRi, tkCurlyRi, tkEof}: + p.hasProgress = false var a = exprColonEqExpr(p) + if not p.hasProgress: break addSon(result, a) if p.tok.tokType == tkComma: getTok(p) @@ -833,6 +854,7 @@ proc parseIdentColonEquals(p: var TParser, flags: TDeclaredIdentFlags): PNode = #| (':' optInd typeDesc)? ('=' optInd expr)?) var a: PNode result = newNodeP(nkIdentDefs, p) + # progress guaranteed while true: case p.tok.tokType of tkSymbol, tkAccent: @@ -870,6 +892,7 @@ proc parseTuple(p: var TParser, indentAllowed = false): PNode = if p.tok.tokType == tkBracketLe: getTok(p) optInd(p, result) + # progress guaranteed while p.tok.tokType in {tkSymbol, tkAccent}: var a = parseIdentColonEquals(p, {}) addSon(result, a) @@ -883,6 +906,7 @@ proc parseTuple(p: var TParser, indentAllowed = false): PNode = if realInd(p): withInd(p): rawSkipComment(p, result) + # progress guaranteed while true: case p.tok.tokType of tkSymbol, tkAccent: @@ -909,6 +933,7 @@ proc parseParamList(p: var TParser, retColon = true): PNode = if hasParLe: getTok(p) optInd(p, result) + # progress guaranteed while true: case p.tok.tokType of tkSymbol, tkAccent: @@ -989,6 +1014,7 @@ proc isExprStart(p: TParser): bool = else: result = false proc parseSymbolList(p: var TParser, result: PNode, allowNil = false) = + # progress guaranteed while true: var s = parseSymbol(p, allowNil) if s.kind == nkEmpty: break @@ -1147,6 +1173,7 @@ proc parseMacroColon(p: var TParser, x: PNode): PNode = let body = parseStmt(p) stmtList.add body #addSon(result, makeStmtList(body)) + # progress guaranteed while sameInd(p): var b: PNode case p.tok.tokType @@ -1246,8 +1273,9 @@ proc parseImport(p: var TParser, kind: TNodeKind): PNode = optInd(p, result) while true: # was: while p.tok.tokType notin {tkEof, tkSad, tkDed}: + p.hasProgress = false a = parseModuleName(p, kind) - if a.kind == nkEmpty: break + if a.kind == nkEmpty or not p.hasProgress: break addSon(result, a) if p.tok.tokType != tkComma: break getTok(p) @@ -1261,8 +1289,9 @@ proc parseIncludeStmt(p: var TParser): PNode = optInd(p, result) while true: # was: while p.tok.tokType notin {tkEof, tkSad, tkDed}: + p.hasProgress = false var a = parseExpr(p) - if a.kind == nkEmpty: break + if a.kind == nkEmpty or not p.hasProgress: break addSon(result, a) if p.tok.tokType != tkComma: break getTok(p) @@ -1280,8 +1309,9 @@ proc parseFromStmt(p: var TParser): PNode = optInd(p, result) while true: # p.tok.tokType notin {tkEof, tkSad, tkDed}: + p.hasProgress = false a = parseExpr(p) - if a.kind == nkEmpty: break + if a.kind == nkEmpty or not p.hasProgress: break addSon(result, a) if p.tok.tokType != tkComma: break getTok(p) @@ -1474,6 +1504,7 @@ proc parseGenericParam(p: var TParser): PNode = #| genericParam = symbol (comma symbol)* (colon expr)? ('=' optInd expr)? var a: PNode result = newNodeP(nkIdentDefs, p) + # progress guaranteed while true: case p.tok.tokType of tkSymbol, tkAccent: @@ -1503,6 +1534,7 @@ proc parseGenericParamList(p: var TParser): PNode = result = newNodeP(nkGenericParams, p) getTok(p) optInd(p, result) + # progress guaranteed while p.tok.tokType in {tkSymbol, tkAccent}: var a = parseGenericParam(p) addSon(result, a) @@ -1566,6 +1598,7 @@ proc parseSection(p: var TParser, kind: TNodeKind, if realInd(p): withInd(p): skipComment(p, result) + # progress guaranteed while sameInd(p): case p.tok.tokType of tkSymbol, tkAccent, tkParLe: @@ -1607,6 +1640,7 @@ proc parseEnum(p: var TParser): PNode = addSon(result, ast.emptyNode) optInd(p, result) flexComment(p, result) + # progress guaranteed while true: var a = parseSymbol(p) if a.kind == nkEmpty: return @@ -1641,6 +1675,7 @@ proc parseObjectWhen(p: var TParser): PNode = #| ('elif' expr colcom objectPart COMMENT?)* #| ('else' colcom objectPart COMMENT?)? result = newNodeP(nkRecWhen, p) + # progress guaranteed while sameInd(p): getTok(p) # skip `when`, `elif` var branch = newNodeP(nkElifBranch, p) @@ -1682,6 +1717,7 @@ proc parseObjectCase(p: var TParser): PNode = if realInd(p): p.currInd = p.tok.indent wasIndented = true + # progress guaranteed while sameInd(p): var b: PNode case p.tok.tokType @@ -1783,6 +1819,7 @@ proc parseTypeClass(p: var TParser): PNode = if p.tok.tokType == tkOf and p.tok.indent < 0: var a = newNodeP(nkOfInherit, p) getTok(p) + # progress guaranteed while true: addSon(a, parseTypeDesc(p)) if p.tok.tokType != tkComma: break @@ -1821,6 +1858,7 @@ proc parseVarTuple(p: var TParser): PNode = result = newNodeP(nkVarTuple, p) getTok(p) # skip '(' optInd(p, result) + # progress guaranteed while p.tok.tokType in {tkSymbol, tkAccent}: var a = identWithPragma(p) addSon(result, a) @@ -1846,6 +1884,7 @@ proc parseBind(p: var TParser, k: TNodeKind): PNode = result = newNodeP(k, p) getTok(p) optInd(p, result) + # progress guaranteed while true: var a = qualifiedIdent(p) addSon(result, a) @@ -1961,8 +2000,10 @@ proc parseStmt(p: var TParser): PNode = # XXX this ensures tnamedparamanonproc still compiles; # deprecate this syntax later break + p.hasProgress = false var a = complexOrSimpleStmt(p) - if a.kind != nkEmpty: + if not p.hasProgress and p.tok.tokType == tkEof: break + if a.kind != nkEmpty and p.hasProgress: addSon(result, a) else: parMessage(p, errExprExpected, p.tok) @@ -1983,18 +2024,22 @@ proc parseStmt(p: var TParser): PNode = while true: if p.tok.indent >= 0: parMessage(p, errInvalidIndentation) + p.hasProgress = false let a = simpleStmt(p) + let err = not p.hasProgress if a.kind == nkEmpty: parMessage(p, errExprExpected, p.tok) result.add(a) if p.tok.tokType != tkSemiColon: break getTok(p) + if err and p.tok.tokType == tkEof: break proc parseAll(p: var TParser): PNode = ## Parses the rest of the input stream held by the parser into a PNode. result = newNodeP(nkStmtList, p) while p.tok.tokType != tkEof: + p.hasProgress = false var a = complexOrSimpleStmt(p) - if a.kind != nkEmpty: + if a.kind != nkEmpty and p.hasProgress: addSon(result, a) else: parMessage(p, errExprExpected, p.tok) @@ -2007,6 +2052,7 @@ proc parseTopLevelStmt(p: var TParser): PNode = ## Implements an iterator which, when called repeatedly, returns the next ## top-level statement or emptyNode if end of stream. result = ast.emptyNode + # progress guaranteed while true: if p.tok.indent != 0: if p.firstTok and p.tok.indent < 0: discard |