core/parser.nim
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# Adapted from: https://github.com/Araq/Nimrod/blob/v0.9.6/lib/pure/json.nim import lexbase, strutils, streams, unicode, tables import types const errorMessages: array [MinParserError, string] = [ "no error", "invalid token", "string expected", "')' expected", "'\"' or \"'\" expected", "'*/' expected", "EOF expected", "expression expected" ] tokToStr: array [MinTokenKind, string] = [ "invalid token", "EOF", "string literal", "int literal", "float literal", "(", ")", "symbol", "true", "false" ] proc open*(my: var MinParser, input: Stream, filename: string) = lexbase.open(my, input) my.filename = filename my.state = @[stateStart] my.kind = eMinError my.a = "" proc close*(my: var MinParser) {.inline.} = lexbase.close(my) proc getInt*(my: MinParser): int {.inline.} = assert(my.kind == eMinInt) return parseint(my.a) proc getFloat*(my: MinParser): float {.inline.} = assert(my.kind == eMinFloat) return parseFloat(my.a) proc kind*(my: MinParser): MinEventKind {.inline.} = return my.kind proc getColumn*(my: MinParser): int {.inline.} = result = getColNumber(my, my.bufpos) proc getLine*(my: MinParser): int {.inline.} = result = my.lineNumber proc getFilename*(my: MinParser): string {.inline.} = result = my.filename proc errorMsg*(my: MinParser, msg: string): string = assert(my.kind == eMinError) result = "$1 [l:$2, c:$3] ERROR - $4" % [ my.filename, $getLine(my), $getColumn(my), msg] proc errorMsg*(my: MinParser): string = assert(my.kind == eMinError) result = errorMsg(my, errorMessages[my.err]) proc errorMsgExpected*(my: MinParser, e: string): string = result = errorMsg(my, e & " expected") proc raiseParseError*(p: MinParser, msg: string) {.noinline, noreturn.} = raise MinParsingError(msg: errorMsgExpected(p, msg)) proc raiseUndefinedError*(p:MinParser, msg: string) {.noinline, noreturn.} = raise MinUndefinedError(msg: errorMsg(p, msg)) #proc error(p: MinParser, msg: string) = # writeln(stderr, p.errorMsg(msg)) # flushFile(stderr) proc parseNumber(my: var MinParser) = var pos = my.bufpos var buf = my.buf if buf[pos] == '-': add(my.a, '-') inc(pos) if buf[pos] == '.': add(my.a, "0.") inc(pos) else: while buf[pos] in Digits: add(my.a, buf[pos]) inc(pos) if buf[pos] == '.': add(my.a, '.') inc(pos) # digits after the dot: while buf[pos] in Digits: add(my.a, buf[pos]) inc(pos) if buf[pos] in {'E', 'e'}: add(my.a, buf[pos]) inc(pos) if buf[pos] in {'+', '-'}: add(my.a, buf[pos]) inc(pos) while buf[pos] in Digits: add(my.a, buf[pos]) inc(pos) my.bufpos = pos proc handleHexChar(c: char, x: var int): bool = result = true # Success case c of '0'..'9': x = (x shl 4) or (ord(c) - ord('0')) of 'a'..'f': x = (x shl 4) or (ord(c) - ord('a') + 10) of 'A'..'F': x = (x shl 4) or (ord(c) - ord('A') + 10) else: result = false # error proc parseString(my: var MinParser): MinTokenKind = result = tkString var pos = my.bufpos + 1 var buf = my.buf while true: case buf[pos] of '\0': my.err = errQuoteExpected result = tkError break of '"': inc(pos) break of '\\': case buf[pos+1] of '\\', '"', '\'', '/': add(my.a, buf[pos+1]) inc(pos, 2) of 'b': add(my.a, '\b') inc(pos, 2) of 'f': add(my.a, '\f') inc(pos, 2) of 'n': add(my.a, '\L') inc(pos, 2) of 'r': add(my.a, '\C') inc(pos, 2) of 't': add(my.a, '\t') inc(pos, 2) of 'u': inc(pos, 2) var r: int if handleHexChar(buf[pos], r): inc(pos) if handleHexChar(buf[pos], r): inc(pos) if handleHexChar(buf[pos], r): inc(pos) if handleHexChar(buf[pos], r): inc(pos) add(my.a, toUTF8(Rune(r))) else: # don't bother with the error add(my.a, buf[pos]) inc(pos) of '\c': pos = lexbase.handleCR(my, pos) buf = my.buf add(my.a, '\c') of '\L': pos = lexbase.handleLF(my, pos) buf = my.buf add(my.a, '\L') else: add(my.a, buf[pos]) inc(pos) my.bufpos = pos # store back proc parseSymbol(my: var MinParser): MinTokenKind = result = tkSymbol var pos = my.bufpos var buf = my.buf if not(buf[pos] in Whitespace): while not(buf[pos] in WhiteSpace) and not(buf[pos] in ['\0', ')', '(']): add(my.a, buf[pos]) inc(pos) my.bufpos = pos proc skip(my: var MinParser) = var pos = my.bufpos var buf = my.buf while true: case buf[pos] of ';': # skip line comment: inc(pos, 2) while true: case buf[pos] of '\0': break of '\c': pos = lexbase.handleCR(my, pos) buf = my.buf break of '\L': pos = lexbase.handleLF(my, pos) buf = my.buf break else: inc(pos) of '/': if buf[pos+1] == '/': # skip line comment: inc(pos, 2) while true: case buf[pos] of '\0': break of '\c': pos = lexbase.handleCR(my, pos) buf = my.buf break of '\L': pos = lexbase.handleLF(my, pos) buf = my.buf break else: inc(pos) elif buf[pos+1] == '*': # skip long comment: inc(pos, 2) while true: case buf[pos] of '\0': my.err = errEOC_Expected break of '\c': pos = lexbase.handleCR(my, pos) buf = my.buf of '\L': pos = lexbase.handleLF(my, pos) buf = my.buf of '*': inc(pos) if buf[pos] == '/': inc(pos) break else: inc(pos) else: break of ' ', '\t': inc(pos) of '\c': pos = lexbase.handleCR(my, pos) buf = my.buf of '\L': pos = lexbase.handleLF(my, pos) buf = my.buf else: break my.bufpos = pos proc getToken*(my: var MinParser): MinTokenKind = setLen(my.a, 0) skip(my) case my.buf[my.bufpos] of '-', '.': if my.bufpos+1 <= my.buf.len and my.buf[my.bufpos+1] in '0'..'9': parseNumber(my) if {'.', 'e', 'E'} in my.a: result = tkFloat else: result = tkInt else: result = parseSymbol(my) of '0'..'9': parseNumber(my) if {'.', 'e', 'E'} in my.a: result = tkFloat else: result = tkInt of '"': result = parseString(my) of '(': inc(my.bufpos) result = tkBracketLe of ')': inc(my.bufpos) result = tkBracketRi of '\0': result = tkEof else: result = parseSymbol(my) case my.a of "true": result = tkTrue of "false": result = tkFalse else: discard my.token = result proc next*(my: var MinParser) = var tk = getToken(my) var i = my.state.len-1 case my.state[i] of stateEof: if tk == tkEof: my.kind = eMinEof else: my.kind = eMinError my.err = errEofExpected of stateStart: case tk of tkString, tkInt, tkFloat, tkTrue, tkFalse: my.state[i] = stateEof # expect EOF next! my.kind = MinEventKind(ord(tk)) of tkBracketLe: my.state.add(stateQuotation) # we expect any my.kind = eMinQuotationStart of tkEof: my.kind = eMinEof else: my.kind = eMinError my.err = errEofExpected of stateQuotation: case tk of tkString, tkInt, tkFloat, tkTrue, tkFalse: my.kind = MinEventKind(ord(tk)) of tkBracketLe: my.state.add(stateQuotation) my.kind = eMinQuotationStart of tkBracketRi: my.kind = eMinQuotationEnd discard my.state.pop() else: my.kind = eMinError my.err = errBracketRiExpected of stateExpectValue: case tk of tkString, tkInt, tkFloat, tkTrue, tkFalse: my.kind = MinEventKind(ord(tk)) of tkBracketLe: my.state.add(stateQuotation) my.kind = eMinQuotationStart else: my.kind = eMinError my.err = errExprExpected proc eat(p: var MinParser, token: MinTokenKind) = if p.token == token: discard getToken(p) else: raiseParseError(p, tokToStr[token]) proc parseMinValue*(p: var MinParser): MinValue = #echo p.a, " (", p.token, ")" case p.token of tkTrue: result = MinValue(kind: minBool, boolVal: true, column: p.getColumn, line: p.lineNumber) discard getToken(p) of tkFalse: result = MinValue(kind: minBool, boolVal: false, column: p.getColumn, line: p.lineNumber) discard getToken(p) of tkString: result = MinValue(kind: minString, strVal: p.a, column: p.getColumn, line: p.lineNumber) p.a = "" discard getToken(p) of tkInt: result = MinValue(kind: minInt, intVal: parseint(p.a), column: p.getColumn, line: p.lineNumber) discard getToken(p) of tkFloat: result = MinValue(kind: minFloat, floatVal: parseFloat(p.a), column: p.getColumn, line: p.lineNumber) discard getToken(p) of tkBracketLe: var q = newSeq[MinValue](0) discard getToken(p) while p.token != tkBracketRi: q.add parseMinValue(p) eat(p, tkBracketRi) result = MinValue(kind: minQuotation, qVal: q, column: p.getColumn, line: p.lineNumber) of tkSymbol: result = MinValue(kind: minSymbol, symVal: p.a, column: p.getColumn, line: p.lineNumber) p.a = "" discard getToken(p) else: raiseUndefinedError(p, "Undefined value: '"&p.a&"'") result.filename = p.filename proc `$`*(a: MinValue): string = case a.kind: of minBool: return $a.boolVal of minSymbol: return a.symVal of minString: return "\""&a.strVal&"\"" of minInt: return $a.intVal of minFloat: return $a.floatVal of minQuotation: var q = "(" for i in a.qVal: q = q & $i & " " q = q.strip & ")" return q proc `$$`*(a: MinValue): string = case a.kind: of minBool: return $a.boolVal of minSymbol: return a.symVal of minString: return a.strVal of minInt: return $a.intVal of minFloat: return $a.floatVal of minQuotation: var q = "(" for i in a.qVal: q = q & $i & " " q = q.strip & ")" return q proc print*(a: MinValue) = stdout.write($$a) proc `==`*(a: MinValue, b: MinValue): bool = if a.kind == minSymbol and b.kind == minSymbol: return a.symVal == b.symVal elif a.kind == minInt and b.kind == minInt: return a.intVal == b.intVal elif a.kind == minInt and b.kind == minFloat: return a.intVal.float == b.floatVal.float elif a.kind == minFloat and b.kind == minFloat: return a.floatVal == b.floatVal elif a.kind == minFloat and b.kind == minInt: return a.floatVal == b.intVal.float elif a.kind == b.kind: if a.kind == minString: return a.strVal == b.strVal elif a.kind == minBool: return a.boolVal == b.boolVal elif a.kind == minQuotation: if a.qVal.len == b.qVal.len: var c = 0 for item in a.qVal: if item == b.qVal[c]: c.inc else: return false return true else: return false else: return false proc isNil*(a: MinValue): bool = return a.kind != minQuotation and a.kind != minString and a.kind != minFloat and a.kind != minInt and a.kind != minBool and a.kind != minSymbol |