diff options
| -rw-r--r-- | changelog.md | 3 | ||||
| -rw-r--r-- | lib/pure/pegs.nim | 23 | ||||
| -rw-r--r-- | tests/stdlib/tpegs.nim | 78 |
3 files changed, 102 insertions, 2 deletions
diff --git a/changelog.md b/changelog.md index 4067cb693..4a490dfdd 100644 --- a/changelog.md +++ b/changelog.md @@ -107,6 +107,9 @@ use the Nim VM in a native Nim application. - Added the parameter ``val`` for the ``CritBitTree[T].incl`` proc. - The proc ``tgamma`` was renamed to ``gamma``. ``tgamma`` is deprecated. +- The ``pegs`` module now exports getters for the fields of its ``Peg`` and ``NonTerminal`` + object types. ``Peg``s with child nodes now have the standard ``items`` and ``pairs`` + iterators. ### Language additions diff --git a/lib/pure/pegs.nim b/lib/pure/pegs.nim index 39c5790ed..d16527a56 100644 --- a/lib/pure/pegs.nim +++ b/lib/pure/pegs.nim @@ -32,7 +32,7 @@ const ## can be captured. More subpatterns cannot be captured! type - PegKind = enum + PegKind* = enum pkEmpty, pkAny, ## any character (.) pkAnyRune, ## any Unicode character (_) @@ -67,7 +67,7 @@ type pkRule, ## a <- b pkList, ## a, b pkStartAnchor ## ^ --> Internal DSL: startAnchor() - NonTerminalFlag = enum + NonTerminalFlag* = enum ntDeclared, ntUsed NonTerminalObj = object ## represents a non terminal symbol name: string ## the name of the symbol @@ -86,6 +86,25 @@ type else: sons: seq[Peg] NonTerminal* = ref NonTerminalObj +proc name*(nt: NonTerminal): string = nt.name +proc line*(nt: NonTerminal): int = nt.line +proc col*(nt: NonTerminal): int = nt.col +proc flags*(nt: NonTerminal): set[NonTerminalFlag] = nt.flags +proc rule*(nt: NonTerminal): Peg = nt.rule + +proc kind*(p: Peg): PegKind = p.kind +proc term*(p: Peg): string = p.term +proc ch*(p: Peg): char = p.ch +proc charChoice*(p: Peg): ref set[char] = p.charChoice +proc nt*(p: Peg): NonTerminal = p.nt +proc index*(p: Peg): range[0..MaxSubpatterns] = p.index +iterator items*(p: Peg): Peg {.inline.} = + for s in p.sons: + yield s +iterator pairs*(p: Peg): (int, Peg) {.inline.} = + for i in 0 ..< p.sons.len: + yield (i, p.sons[i]) + proc term*(t: string): Peg {.nosideEffect, rtl, extern: "npegs$1Str".} = ## constructs a PEG from a terminal string if t.len != 1: diff --git a/tests/stdlib/tpegs.nim b/tests/stdlib/tpegs.nim new file mode 100644 index 000000000..e5b709a66 --- /dev/null +++ b/tests/stdlib/tpegs.nim @@ -0,0 +1,78 @@ +discard """ + output: ''' +pkNonTerminal: Sum @(2, 3) + pkSequence: (Product (('+' / '-') Product)*) + pkNonTerminal: Product @(3, 7) + pkSequence: (Value (('*' / '/') Value)*) + pkNonTerminal: Value @(4, 5) + pkOrderedChoice: (([0-9] [0-9]*) / ('(' Expr ')')) + pkSequence: ([0-9] [0-9]*) + pkCharChoice: [0-9] + pkGreedyRepSet: [0-9]* + pkSequence: ('(' Expr ')') + pkChar: '(' + pkNonTerminal: Expr @(1, 4) + pkNonTerminal: Sum @(2, 3) + pkChar: ')' + pkGreedyRep: (('*' / '/') Value)* + pkSequence: (('*' / '/') Value) + pkOrderedChoice: ('*' / '/') + pkChar: '*' + pkChar: '/' + pkNonTerminal: Value @(4, 5) + pkGreedyRep: (('+' / '-') Product)* + pkSequence: (('+' / '-') Product) + pkOrderedChoice: ('+' / '-') + pkChar: '+' + pkChar: '-' + pkNonTerminal: Product @(3, 7) +''' +""" + +import strutils, streams +import pegs + +const + indent = " " + +let + pegSrc = """ +Expr <- Sum +Sum <- Product (('+' / '-') Product)* +Product <- Value (('*' / '/') Value)* +Value <- [0-9]+ / '(' Expr ')' + """ + pegAst: Peg = pegSrc.peg + +var + outp = newStringStream() + processed: seq[string] = @[] + +proc prt(outp: Stream, kind: PegKind, s: string; level: int = 0) = + outp.writeLine indent.repeat(level) & "$1: $2" % [$kind, s] + +proc recLoop(p: Peg, level: int = 0) = + case p.kind + of pkEmpty..pkWhitespace: + discard + of pkTerminal, pkTerminalIgnoreCase, pkTerminalIgnoreStyle: + outp.prt(p.kind, $p, level) + of pkChar, pkGreedyRepChar: + outp.prt(p.kind, $p, level) + of pkCharChoice, pkGreedyRepSet: + outp.prt(p.kind, $p, level) + of pkNonTerminal: + outp.prt(p.kind, + "$1 @($3, $4)" % [p.nt.name, $p.nt.rule.kind, $p.nt.line, $p.nt.col], level) + if not(p.nt.name in processed): + processed.add p.nt.name + p.nt.rule.recLoop level+1 + of pkBackRef..pkBackRefIgnoreStyle: + outp.prt(p.kind, $p, level) + else: + outp.prt(p.kind, $p, level) + for s in items(p): + s.recLoop level+1 + +pegAst.recLoop +echo outp.data \ No newline at end of file |