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Merge pull request #4136 from oderwat/HARA-peg-replace-cb

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Added a replace() with callback to pegs.
This commit is contained in:
Andreas Rumpf 2016-05-11 23:31:22 +02:00
commit 34110fc118
1 changed files with 59 additions and 0 deletions
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59
lib/pure/pegs.nim
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@ -962,6 +962,50 @@ proc parallelReplace*(s: string, subs: varargs[
# copy the rest: # copy the rest:
add(result, substr(s, i)) add(result, substr(s, i))
proc replace*(s: string, sub: Peg, cb: proc(
match: int, cnt: int, caps: openArray[string]): string): string {.
rtl, extern: "npegs$1cb".}=
## Replaces `sub` in `s` by the resulting strings from the callback.
## 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
##
## proc handleMatches*(m: int, n: int, c: openArray[string]): string =
## result = ""
## if m > 0:
## result.add ", "
## result.add case n:
## of 2: c[0].toLower & ": '" & c[1] & "'"
## of 1: c[0].toLower & ": ''"
## else: ""
##
## let s = "Var1=key1;var2=Key2; VAR3"
## echo s.replace(peg"{\ident}('='{\ident})* ';'* \s*", handleMatches)
##
## Results in:
##
## .. code-block:: nim
##
## "var1: 'key1', var2: 'Key2', var3: ''"
result = ""
var i = 0
var caps: array[0..MaxSubpatterns-1, string]
var c: Captures
var m = 0
while i < s.len:
c.ml = 0
var x = rawMatch(s, sub, i, c)
if x <= 0:
add(result, s[i])
inc(i)
else:
fillMatches(s, caps, c)
add(result, cb(m, c.ml, caps))
inc(i, x)
inc(m)
add(result, substr(s, i))
proc transformFile*(infile, outfile: string, proc transformFile*(infile, outfile: string,
subs: varargs[tuple[pattern: Peg, repl: string]]) {. subs: varargs[tuple[pattern: Peg, repl: string]]) {.
rtl, extern: "npegs$1".} = rtl, extern: "npegs$1".} =
@ -1789,3 +1833,18 @@ when isMainModule:
assert(str.find(empty_test) == 0) assert(str.find(empty_test) == 0)
assert(str.match(empty_test)) assert(str.match(empty_test))
proc handleMatches*(m: int, n: int, c: openArray[string]): string =
result = ""
if m > 0:
result.add ", "
result.add case n:
of 2: c[0].toLower & ": '" & c[1] & "'"
of 1: c[0].toLower & ": ''"
else: ""
assert("Var1=key1;var2=Key2; VAR3".
replace(peg"{\ident}('='{\ident})* ';'* \s*",
handleMatches)=="var1: 'key1', var2: 'Key2', var3: ''")