diff options
Diffstat (limited to 'lib/pure/pegs.nim')
| -rw-r--r-- | lib/pure/pegs.nim | 177 |
1 files changed, 91 insertions, 86 deletions
diff --git a/lib/pure/pegs.nim b/lib/pure/pegs.nim index 5827b7444..2969fd6d7 100644 --- a/lib/pure/pegs.nim +++ b/lib/pure/pegs.nim @@ -22,11 +22,11 @@ when defined(nimPreviewSlimSystem): const useUnicode = true ## change this to deactivate proper UTF-8 support -import strutils, macros +import std/[strutils, macros] import std/private/decode_helpers when useUnicode: - import unicode + import std/unicode export unicode.`==` const @@ -168,8 +168,9 @@ func charSet*(s: set[char]): Peg {.rtl, extern: "npegs$1".} = ## constructs a PEG from a character set `s` assert '\0' notin s result = Peg(kind: pkCharChoice) - new(result.charChoice) - result.charChoice[] = s + {.cast(noSideEffect).}: + new(result.charChoice) + result.charChoice[] = s func len(a: Peg): int {.inline.} = return a.sons.len func add(d: var Peg, s: Peg) {.inline.} = add(d.sons, s) @@ -313,21 +314,21 @@ func capture*(a: Peg = Peg(kind: pkEmpty)): Peg {.rtl, extern: "npegsCapture".} func backref*(index: range[1..MaxSubpatterns], reverse: bool = false): Peg {. rtl, extern: "npegs$1".} = ## constructs a back reference of the given `index`. `index` starts counting - ## from 1. `reverse` specifies wether indexing starts from the end of the + ## from 1. `reverse` specifies whether indexing starts from the end of the ## capture list. result = Peg(kind: pkBackRef, index: (if reverse: -index else: index - 1)) func backrefIgnoreCase*(index: range[1..MaxSubpatterns], reverse: bool = false): Peg {. rtl, extern: "npegs$1".} = ## constructs a back reference of the given `index`. `index` starts counting - ## from 1. `reverse` specifies wether indexing starts from the end of the + ## from 1. `reverse` specifies whether indexing starts from the end of the ## capture list. Ignores case for matching. result = Peg(kind: pkBackRefIgnoreCase, index: (if reverse: -index else: index - 1)) func backrefIgnoreStyle*(index: range[1..MaxSubpatterns], reverse: bool = false): Peg {. rtl, extern: "npegs$1".} = ## constructs a back reference of the given `index`. `index` starts counting - ## from 1. `reverse` specifies wether indexing starts from the end of the + ## from 1. `reverse` specifies whether indexing starts from the end of the ## capture list. Ignores style for matching. result = Peg(kind: pkBackRefIgnoreStyle, index: (if reverse: -index else: index - 1)) @@ -561,7 +562,7 @@ template matchOrParse(mopProc: untyped) = # procs. For the former, *enter* and *leave* event handler code generators # are provided which just return *discard*. - proc mopProc(s: string, p: Peg, start: int, c: var Captures): int {.gcsafe.} = + proc mopProc(s: string, p: Peg, start: int, c: var Captures): int {.gcsafe, raises: [].} = proc matchBackRef(s: string, p: Peg, start: int, c: var Captures): int = # Parse handler code must run in an *of* clause of its own for each # *PegKind*, so we encapsulate the identical clause body for @@ -888,7 +889,7 @@ macro mkHandlerTplts(handlers: untyped): untyped = # Transforms the handler spec in *handlers* into handler templates. # The AST structure of *handlers[0]*: # - # .. code-block:: + # ``` # StmtList # Call # Ident "pkNonTerminal" @@ -909,6 +910,7 @@ macro mkHandlerTplts(handlers: untyped): untyped = # StmtList # <handler code block> # ... + # ``` func mkEnter(hdName, body: NimNode): NimNode = template helper(hdName, body) {.dirty.} = template hdName(s, p, start) = @@ -958,60 +960,61 @@ template eventParser*(pegAst, handlers: untyped): (proc(s: string): int) = ## match, else the length of the total match. The following example code ## evaluates an arithmetic expression defined by a simple PEG: ## - ## .. code-block:: nim - ## import std/[strutils, pegs] + ## ```nim + ## import std/[strutils, pegs] ## - ## let - ## pegAst = """ - ## Expr <- Sum - ## Sum <- Product (('+' / '-')Product)* - ## Product <- Value (('*' / '/')Value)* - ## Value <- [0-9]+ / '(' Expr ')' - ## """.peg - ## txt = "(5+3)/2-7*22" + ## let + ## pegAst = """ + ## Expr <- Sum + ## Sum <- Product (('+' / '-')Product)* + ## Product <- Value (('*' / '/')Value)* + ## Value <- [0-9]+ / '(' Expr ')' + ## """.peg + ## txt = "(5+3)/2-7*22" ## - ## var - ## pStack: seq[string] = @[] - ## valStack: seq[float] = @[] - ## opStack = "" - ## let - ## parseArithExpr = pegAst.eventParser: - ## pkNonTerminal: - ## enter: - ## pStack.add p.nt.name - ## leave: - ## pStack.setLen pStack.high - ## if length > 0: - ## let matchStr = s.substr(start, start+length-1) - ## case p.nt.name - ## of "Value": - ## try: - ## valStack.add matchStr.parseFloat - ## echo valStack - ## except ValueError: - ## discard - ## of "Sum", "Product": - ## try: - ## let val = matchStr.parseFloat - ## except ValueError: - ## if valStack.len > 1 and opStack.len > 0: - ## valStack[^2] = case opStack[^1] - ## of '+': valStack[^2] + valStack[^1] - ## of '-': valStack[^2] - valStack[^1] - ## of '*': valStack[^2] * valStack[^1] - ## else: valStack[^2] / valStack[^1] - ## valStack.setLen valStack.high - ## echo valStack - ## opStack.setLen opStack.high - ## echo opStack - ## pkChar: - ## leave: - ## if length == 1 and "Value" != pStack[^1]: - ## let matchChar = s[start] - ## opStack.add matchChar - ## echo opStack + ## var + ## pStack: seq[string] = @[] + ## valStack: seq[float] = @[] + ## opStack = "" + ## let + ## parseArithExpr = pegAst.eventParser: + ## pkNonTerminal: + ## enter: + ## pStack.add p.nt.name + ## leave: + ## pStack.setLen pStack.high + ## if length > 0: + ## let matchStr = s.substr(start, start+length-1) + ## case p.nt.name + ## of "Value": + ## try: + ## valStack.add matchStr.parseFloat + ## echo valStack + ## except ValueError: + ## discard + ## of "Sum", "Product": + ## try: + ## let val = matchStr.parseFloat + ## except ValueError: + ## if valStack.len > 1 and opStack.len > 0: + ## valStack[^2] = case opStack[^1] + ## of '+': valStack[^2] + valStack[^1] + ## of '-': valStack[^2] - valStack[^1] + ## of '*': valStack[^2] * valStack[^1] + ## else: valStack[^2] / valStack[^1] + ## valStack.setLen valStack.high + ## echo valStack + ## opStack.setLen opStack.high + ## echo opStack + ## pkChar: + ## leave: + ## if length == 1 and "Value" != pStack[^1]: + ## let matchChar = s[start] + ## opStack.add matchChar + ## echo opStack ## - ## let pLen = parseArithExpr(txt) + ## let pLen = parseArithExpr(txt) + ## ``` ## ## The *handlers* parameter consists of code blocks for *PegKinds*, ## which define the grammar elements of interest. Each block can contain @@ -1041,10 +1044,10 @@ template eventParser*(pegAst, handlers: untyped): (proc(s: string): int) = # by *mkHandlerTplts*. template mkDoEnter(hdPostf, s, pegNode, start) = when declared(`enter hdPostf`): - `enter hdPostf`(s, pegNode, start): + `enter hdPostf`(s, pegNode, start) else: discard - let hdPostf = ident(substr(strVal(pegKind), 2)) + let hdPostf = ident(substr($pegKind, 2)) getAst(mkDoEnter(hdPostf, s, pegNode, start)) macro leave(pegKind, s, pegNode, start, length: untyped): untyped = @@ -1052,10 +1055,10 @@ template eventParser*(pegAst, handlers: untyped): (proc(s: string): int) = # a grammar element of kind *pegKind*. template mkDoLeave(hdPostf, s, pegNode, start, length) = when declared(`leave hdPostf`): - `leave hdPostf`(s, pegNode, start, length): + `leave hdPostf`(s, pegNode, start, length) else: discard - let hdPostf = ident(substr(strVal(pegKind), 2)) + let hdPostf = ident(substr($pegKind, 2)) getAst(mkDoLeave(hdPostf, s, pegNode, start, length)) matchOrParse(parseIt) @@ -1180,8 +1183,7 @@ template `=~`*(s: string, pattern: Peg): bool = ## This calls ``match`` with an implicit declared ``matches`` array that ## can be used in the scope of the ``=~`` call: ## - ## .. code-block:: nim - ## + ## ```nim ## if line =~ peg"\s* {\w+} \s* '=' \s* {\w+}": ## # matches a key=value pair: ## echo("Key: ", matches[0]) @@ -1193,10 +1195,10 @@ template `=~`*(s: string, pattern: Peg): bool = ## echo("comment: ", matches[0]) ## else: ## echo("syntax error") - ## + ## ``` bind MaxSubpatterns when not declaredInScope(matches): - var matches {.inject.}: array[0..MaxSubpatterns-1, string] + var matches {.inject.} = default(array[0..MaxSubpatterns-1, string]) match(s, pattern, matches) # ------------------------- more string handling ------------------------------ @@ -1229,14 +1231,15 @@ func replacef*(s: string, sub: Peg, by: string): string {. ## Replaces `sub` in `s` by the string `by`. Captures can be accessed in `by` ## with the notation ``$i`` and ``$#`` (see strutils.`%`). Examples: ## - ## .. code-block:: nim + ## ```nim ## "var1=key; var2=key2".replacef(peg"{\ident}'='{\ident}", "$1<-$2$2") + ## ``` ## ## Results in: ## - ## .. code-block:: nim - ## + ## ```nim ## "var1<-keykey; val2<-key2key2" + ## ``` result = "" var i = 0 var caps: array[0..MaxSubpatterns-1, string] @@ -1304,8 +1307,7 @@ func replace*(s: string, sub: Peg, cb: proc( ## The callback proc receives the index of the current match (starting with 0), ## the count of captures and an open array with the captures of each match. Examples: ## - ## .. code-block:: nim - ## + ## ```nim ## func handleMatches*(m: int, n: int, c: openArray[string]): string = ## result = "" ## if m > 0: @@ -1317,12 +1319,13 @@ func replace*(s: string, sub: Peg, cb: proc( ## ## let s = "Var1=key1;var2=Key2; VAR3" ## echo s.replace(peg"{\ident}('='{\ident})* ';'* \s*", handleMatches) + ## ``` ## ## Results in: ## - ## .. code-block:: nim - ## + ## ```nim ## "var1: 'key1', var2: 'Key2', var3: ''" + ## ``` result = "" var i = 0 var caps: array[0..MaxSubpatterns-1, string] @@ -1360,18 +1363,19 @@ iterator split*(s: string, sep: Peg): string = ## Substrings are separated by the PEG `sep`. ## Examples: ## - ## .. code-block:: nim + ## ```nim ## for word in split("00232this02939is39an22example111", peg"\d+"): ## writeLine(stdout, word) + ## ``` ## ## Results in: ## - ## .. code-block:: nim + ## ```nim ## "this" ## "is" ## "an" ## "example" - ## + ## ``` var c: Captures var first = 0 @@ -1823,9 +1827,7 @@ type skip: Peg func pegError(p: PegParser, msg: string, line = -1, col = -1) = - var e: ref EInvalidPeg - new(e) - e.msg = errorStr(p, msg, line, col) + var e = (ref EInvalidPeg)(msg: errorStr(p, msg, line, col)) raise e func getTok(p: var PegParser) = @@ -1909,7 +1911,8 @@ func primary(p: var PegParser): Peg = getTok(p) elif not arrowIsNextTok(p): var nt = getNonTerminal(p, p.tok.literal) - incl(nt.flags, ntUsed) + {.cast(noSideEffect).}: + incl(nt.flags, ntUsed) result = nonterminal(nt).token(p) getTok(p) else: @@ -2002,12 +2005,14 @@ func parseRule(p: var PegParser): NonTerminal = result = getNonTerminal(p, p.tok.literal) if ntDeclared in result.flags: pegError(p, "attempt to redefine: " & result.name) - result.line = getLine(p) - result.col = getColumn(p) + {.cast(noSideEffect).}: + result.line = getLine(p) + result.col = getColumn(p) getTok(p) eat(p, tkArrow) - result.rule = parseExpr(p) - incl(result.flags, ntDeclared) # NOW inlining may be attempted + {.cast(noSideEffect).}: + result.rule = parseExpr(p) + incl(result.flags, ntDeclared) # NOW inlining may be attempted else: pegError(p, "rule expected, but found: " & p.tok.literal) |