From f017eadc97b041e678196cb2b72c3c66767e7ab0 Mon Sep 17 00:00:00 2001
From: quantimnot <54247259+quantimnot@users.noreply.github.com>
Date: Mon, 4 Oct 2021 15:27:13 -0400
Subject: [PATCH] Add support for `strictEffects` to `std/pegs` (#18949)

* Add support for `strictEffects` to `std/pegs`

* Fixed support of older Nim versions

Co-authored-by: quantimnot <quantimnot@users.noreply.github.com>
---
 lib/pure/pegs.nim      | 5 ++++-
 tests/stdlib/tpegs.nim | 3 +++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/pure/pegs.nim b/lib/pure/pegs.nim
index b6b05cdc11..11270e34ca 100644
--- a/lib/pure/pegs.nim
+++ b/lib/pure/pegs.nim
@@ -1285,9 +1285,12 @@ proc parallelReplace*(s: string, subs: varargs[
   # copy the rest:
   add(result, substr(s, i))
 
+when not defined(nimHasEffectsOf):
+  {.pragma: effectsOf.}
+
 proc replace*(s: string, sub: Peg, cb: proc(
               match: int, cnt: int, caps: openArray[string]): string): string {.
-              rtl, extern: "npegs$1cb".} =
+              rtl, extern: "npegs$1cb", effectsOf: cb.} =
   ## 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:
diff --git a/tests/stdlib/tpegs.nim b/tests/stdlib/tpegs.nim
index 1261d55b81..c3d8942cff 100644
--- a/tests/stdlib/tpegs.nim
+++ b/tests/stdlib/tpegs.nim
@@ -51,6 +51,9 @@ Event parser output
 '''
 """
 
+when defined(nimHasEffectsOf):
+  {.experimental: "strictEffects".}
+
 import std/[strutils, streams, pegs]
 
 const