feat: Add bash-error

It is best to have one library for common Bash things. So, `bash-error`
was merged into here, `bash-core`

Author: hyperupcall

pkg/lib/public/bash-core.sh

@@ -186,3 +186,25 @@ core.shopt_pop() {
 
 	___global_shopt_stack___=("${___global_shopt_stack___[@]::${#___global_shopt_stack___[@]}-2}")
 }
+
+# Variables not checked: 'MAKE_TERMOUT', 'MAKE_TERMERR'
+
+# TODO: 'COLORTERM'
+core.should_color_output() {
+	# https://no-color.org
+	if [[ -v NO_COLOR ]]; then
+		return 1
+	fi
+
+	# 0 => 2 colors
+	# 1 => 16 colors
+	# 2 => 256 colors
+	# 3 => 16,777,216 colors
+	if [[ -v FORCE_COLOR ]]; then
+		return 0
+	fi
+
+	if [[ $TERM == dumb ]]; then
+		return 0
+	fi
+}

pkg/lib/public/error.sh

@@ -0,0 +1,32 @@
+# TODO: deprecate public/bash-error.sh
+
+core.err_set() {
+	if (($# == 1)); then
+		ERRCODE=1
+		ERR="$1"
+	elif (($# == 2)); then
+		ERRCODE="$1"
+		ERR="$2"
+	else
+		printf '%s\n' "Error: bash-error: Incorrect function arguments"
+		return 1
+	fi
+
+	if [ -z "$ERR" ]; then
+		printf '%s\n' "Error: bash-error: Argument for 'ERR' cannot be empty"
+		return 1
+	fi
+}
+
+core.err_clear() {
+	ERRCODE=
+	ERR=
+}
+
+core.err_exists() {
+	if [ -z "$ERR" ]; then
+		return 1
+	else
+		return 0
+	fi
+}

tests/error.bats

@@ -0,0 +1,28 @@
+#!/usr/bin/env bats
+
+load './util/init.sh'
+
+@test "core.err_exists works when set" {
+	# Function sets error when it fails
+	core.err_set 1 "Failed to eat grass"
+
+	# Callsite notices failure, and checks error
+	core.err_exists
+}
+
+@test "core.err_exists works when not set 1" {
+	! core.err_exists
+}
+
+@test "core.err_exists works when not set 2" {
+	core.err_clear
+
+	! core.err_exists
+}
+
+@test "core.err_set sets variables correctly" {
+	core.err_set 2 "value_woof"
+
+	[ "$ERRCODE" = 2 ]
+	[ "$ERR" = 'value_woof' ]
+}