From 1cbaea9574d7d03c5fa33809fcdc87ceb38ea399 Mon Sep 17 00:00:00 2001
From: dubo-dubon-duponey <dubodubonduponey+github@pm.me>
Date: Sat, 1 Dec 2018 22:00:15 -0800
Subject: [PATCH] Work around gnu grep attempt #1

Signed-off-by: dubo-dubon-duponey <dubodubonduponey+github@pm.me>
---
 source/core/abash.sh     |  8 ++++++++
 source/core/commander.sh | 13 +++++++++++--
 tests/unit/arg.sh        | 14 ++++++++++++++
 3 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 tests/unit/arg.sh

diff --git a/source/core/abash.sh b/source/core/abash.sh
index bcaf9a1..0d480d8 100644
--- a/source/core/abash.sh
+++ b/source/core/abash.sh
@@ -17,3 +17,11 @@ _have_bash(){
 }
 
 _have_bash
+
+_gnu_grep(){
+  if grep --version | grep -q gnu; then
+    readonly _GNUGREP="true"
+  fi
+}
+
+_gnu_grep
diff --git a/source/core/commander.sh b/source/core/commander.sh
index edaded8..1912752 100644
--- a/source/core/commander.sh
+++ b/source/core/commander.sh
@@ -72,7 +72,11 @@ dc::commander::declare::arg(){
   local optional="$3"
   local fancy="$4"
   local description="$5"
-  local gf="${6:--Ei}"
+  if [ "$_GNUGREP" ]; then
+    gf="${6:--Pi}"
+  else
+    gf="${6:--Ei}"
+  fi
 
   local var="DC_PARGV_$number"
   local varexist="DC_PARGE_$number"
@@ -122,7 +126,12 @@ dc::commander::declare::flag(){
   local optional="$3"
   local description="$4"
   local alias="$5"
-  local gf="${6:--Ei}"
+  local gf
+  if [ "$_GNUGREP" ]; then
+    gf="${6:--Pi}"
+  else
+    gf="${6:--Ei}"
+  fi
 
   local display="--$name"
   local long="--$name"
diff --git a/tests/unit/arg.sh b/tests/unit/arg.sh
new file mode 100644
index 0000000..7927756
--- /dev/null
+++ b/tests/unit/arg.sh
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+testArgGrep() {
+  DC_PARGV_1=foobar
+  DC_PARGE_1=true
+  local result
+  result="$(dc::commander::declare::arg 1 "^foo(?:bar)?$" "" "a flag" "a flag")"
+  local exit=$?
+  dc-tools::assert::equal "$exit" "0"
+
+  result="$(dc::commander::declare::arg 1 "^foo(?:abar)?$" "" "another flag" "another flag")"
+  local exit=$?
+  dc-tools::assert::equal "$exit" "$ERROR_ARGUMENT_INVALID"
+}