If Bash is available, use process substitution.

3 files changed, 29 insertions, 3 deletions

diff --git a/cppawk b/cppawk
index 3eab7e8..af17e5c 100755
--- a/cppawk
+++ b/cppawk
@@ -34,6 +34,12 @@ awk=gawk
 prepro_opts="-D__gawk__=1 -D__cppawk_ver=20220324"
 
 # globals
+bash=${BASH_VERSION+y}
+# if this isn't bash, and there is a /bin/bash, let's re-execute ourselves
+# with Bash, so we can use process substitution instead of temp files.
+if ! [ $bash ] && [ -x /bin/bash ] ; then
+   exec /bin/bash "$0" "$@"
+fi
 awk_file=
 awk_opts=
 tmp_file=
@@ -128,6 +134,9 @@ while [ $# -gt 0 ] ; do
         ;;
     esac
     ;;
+  --nobash )
+    bash=
+    ;;
   -U* | -D* | -I* | -iquote* )
     prepro_opts="$prepro_opts $(quote "$1")"
     ;;
@@ -171,6 +180,10 @@ if [ -n "$awk_file" ] ; then
   if [ $prepro_only ] ; then
     delhashbang_setline "$awk_file" \
     | eval "$prepro $incopt\"$awk_file_dir\" $prepro_opts - | collapse"
+  elif [ $bash ] ; then
+    prep='delhashbang_setline "$awk_file" \
+         | eval "$prepro $incopt\"$awk_file_dir\" $prepro_opts - | collapse"'
+    eval "$awk $awk_opts -f <($prep) -- \"\$@\""
   else
     trap 'rm -f $tmp_file' EXIT INT TERM
     tmp_file=$(mktemp)
@@ -183,6 +196,11 @@ elif [ $# -gt 0 ] ; then
   if [ $prepro_only ] ; then
     printf "%s" "$1" | delhashbang \
     | eval "$prepro $incopt"$(pwd)" $prepro_opts - | collapse"
+  elif [ $bash ] ; then
+    code=$1; shift
+    prep='printf "%s" "$code" | delhashbang \
+          | eval "$prepro $incopt"$(pwd)" $prepro_opts - | collapse"'
+    eval "$awk $awk_opts -f <($prep) -- \"\$@\""
   else
     trap 'rm -f $tmp_file' EXIT INT TERM
     tmp_file=$(mktemp)
diff --git a/cppawk.1 b/cppawk.1
index 4a70a17..9aed0b5 100644
--- a/cppawk.1
+++ b/cppawk.1
@@ -84,6 +84,12 @@ is then invoked on this file. The file is deleted when
 .B awk
 terminates.
 
+.IP "\fB\-\-nobash\fR"
+Pretend that the shell which executes
+.B cppawk
+isn't GNU Bash, even if it is. This has the effect of disabling
+the use of process substitution in favor of the use of a temporary file.
+
 .IP "\fB\-M\fR, \fB\--bignum\fR"
 These two equivalent GNU Awk options are passed through to
 .BR awk ,
diff --git a/testcases b/testcases
index 40933af..bf22d66 100644
--- a/testcases
+++ b/testcases
@@ -177,8 +177,10 @@ foo_bar
 foo_bar
 --
 32:
-./cppawk --awk=./testdir/testawk foo
+./cppawk --awk=./testdir/testawk foo ;
+./cppawk --nobash --awk=./testdir/testawk foo
 :
+[-f][/d][--]
 [-f][/t][--]
 --
 33:
@@ -197,9 +199,9 @@ mawk=1
 gawk=__gawk__
 --
 36:
-./cppawk --prepro=die --prepro-only x 2>&1 | grep 'not found'
+./cppawk --prepro=die --prepro-only x 2>&1 | (grep -q 'die.*not found' && echo "good")
 :
-./cppawk: 1: eval: die: not found
+good
 --
 37:
 tmp=$(./cppawk --awk=testdir/testdel 1); [ -e $tmp ] || echo gone