From 9b9fdbda81790c06973d77c4b3c5b75be9dbebde Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Fri, 18 Mar 2022 09:17:22 -0700
Subject: Handle quoting properly.

The problem is that if $var holds escaped syntax, we
cannot just use it as command $var; the quotes become
part of the argument. We must get the shell to process the
quoted syntax, which requires eval. For this we define
a function which lets us do command $(syntax "$var").
---
 cppawk    | 20 +++++++++++++++-----
 testcases |  5 +++++
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/cppawk b/cppawk
index d91b2e1..d89059b 100755
--- a/cppawk
+++ b/cppawk
@@ -41,6 +41,8 @@ delhashbang="sed -e /^#!/d"
 prepro_only=
 
 # functions
+
+# convert argument into shell syntax that expands into that argument
 shell_escape()
 {
   case $1 in
@@ -66,6 +68,12 @@ shell_escape()
   esac
 }
 
+# expand shell syntax for interpolation into command line
+syntax()
+{
+  eval printf \"%s \" "$1"
+}
+
 die()
 {
    fmt="$0: $1\n" ; shift
@@ -120,18 +128,20 @@ trap 'rm -f $tmp_file' EXIT INT TERM
 
 if [ -n "$awk_file" ] ; then
   tmp_file=$(mktemp)
-  $delhashbang "$awk_file" | $prepro $prepro_opts - > $tmp_file
-  [ $prepro_only ] && cat $tmp_file || $awk $awk_opts -f $tmp_file "$@"
+  $delhashbang "$awk_file" | $prepro $(syntax "$prepro_opts") - > $tmp_file
+  [ $prepro_only ] \
+    && cat $tmp_file \
+    || $awk $(syntax "$awk_opts") -f $tmp_file "$@"
 elif [ $# -gt 0 ] ; then
   tmp_file=$(mktemp)
   if [ $prepro_only ] ; then
     printf "%s" "$1" | $delhashbang | \
-      $prepro $incopt"$(pwd)" $prepro_opts -
+      $prepro $incopt"$(pwd)" $(syntax $prepro_opts) -
   else
     printf "%s" "$1" | $delhashbang | \
-      $prepro $incopt"$(pwd)" $prepro_opts - > $tmp_file
+      $prepro $incopt"$(pwd)" $(syntax "$prepro_opts") - > $tmp_file
     shift
-    $awk $awk_opts -f $tmp_file "$@"
+    $awk $(syntax "$awk_opts") -f $tmp_file "$@"
   fi
 else
   die "awk code must be specified"
diff --git a/testcases b/testcases
index 04e90dd..71b9169 100644
--- a/testcases
+++ b/testcases
@@ -116,3 +116,8 @@ gawk
 ./cppawk --prepro-only 'BEGIN { }' | grep BEGIN
 :
 BEGIN { }
+--
+22:
+./cppawk -v foo="'\"" 'BEGIN { print foo }'
+:
+'"
-- 
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