Add experimental pager support to batgrep

lib/pager.sh

@@ -0,0 +1,95 @@
+#!/usr/bin/env bash
+# -----------------------------------------------------------------------------
+# bat-extras | Copyright (C) 2019 eth-p | MIT License
+#
+# Repository: https://github.com/eth-p/bat-extras
+# Issues:     https://github.com/eth-p/bat-extras/issues
+# -----------------------------------------------------------------------------
+
+# Defaults.
+SCRIPT_PAGER_CMD=("$PAGER")
+SCRIPT_PAGER_ARGS=()
+
+# Add arguments for the less pager.
+if [[ "$(basename "${SCRIPT_PAGER_CMD[0]}")" = "less" ]]; then
+	SCRIPT_PAGER_ARGS=(-R)
+fi
+
+# Prefer the bat pager.
+if [[ -n "${BAT_PAGER+x}" ]]; then
+	SCRIPT_PAGER_CMD=($BAT_PAGER)
+	SCRIPT_PAGER_ARGS=()
+fi
+
+# Prefer no pager if not a tty.
+if ! [[ -t 1 ]]; then
+	SCRIPT_PAGER_CMD=()
+	SCRIPT_PAGER_ARGS=()
+fi
+
+# -----------------------------------------------------------------------------
+
+# Parse arguments for the pager.
+# This should be called inside the shiftopt/shiftval loop.
+#
+# Example:
+#     while shiftopt; do
+#         case "$OPT" in
+#             # ...
+#         esac
+#         pager_shiftopt && continue
+#     done
+pager_shiftopt() {
+	case "$OPT" in
+		# Specify paging.
+		--no-pager)   shiftval; SCRIPT_PAGER_CMD='';;
+		--paging)     shiftval; {
+			case "$OPT_VAL" in
+				never)  SCRIPT_PAGER_CMD='';;
+				always) :;;
+				auto)   :;;
+			esac
+		};;
+
+		# Specify the pager.
+		--pager) {
+			shiftval;
+			SCRIPT_PAGER_CMD=($OPT_VAL);
+			PAGER_ARGS=()
+		};;
+
+		*) return 1;;
+	esac
+
+	return 0
+}
+
+# Executes a command or function, and pipes its output to the pager (if exists).
+#
+# Returns: The exit code of the command.
+# Example:
+#     pager_exec echo hi
+pager_exec() {
+	if [[ -n "$1" ]]; then
+		if [[ -n "$SCRIPT_PAGER_CMD" ]]; then
+			"$@" | "${SCRIPT_PAGER_CMD[@]}" "${SCRIPT_PAGER_ARGS[@]}"
+			return $?
+		else
+			"$@"
+			return $?
+		fi
+	fi
+}
+
+# Displays the output of a command or function inside the pager (if exists).
+#
+# Example:
+#     bat | pager_display
+pager_display() {
+	if [[ -n "$SCRIPT_PAGER_CMD" ]]; then
+		"${SCRIPT_PAGER_CMD[@]}" "${SCRIPT_PAGER_ARGS[@]}"
+	else
+		cat
+	fi
+}
+

src/batgrep.sh

@@ -8,6 +8,7 @@
 LIB="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/../lib"
 BAT="bat"
 source "${LIB}/print.sh"
+source "${LIB}/pager.sh"
 source "${LIB}/opt.sh"
 source "${LIB}/version.sh"
 # -----------------------------------------------------------------------------
@@ -21,6 +22,7 @@ OPT_CONTEXT_AFTER=2
 OPT_FOLLOW=true
 OPT_SNIP=""
 OPT_HIGHLIGHT=true
+OPT_COLOR=false
 BAT_STYLE="header,numbers"
 
 # Set options based on the bat version.
@@ -28,6 +30,11 @@ if version_compare "$(bat_version)" -gt "0.12"; then
 	OPT_SNIP=",snip"
 fi
 
+# Set options based on tty.
+if [[ -t 1 ]]; then
+	OPT_COLOR=true
+fi
+
 # Parse arguments.
 while shiftopt; do
 	case "$OPT" in
@@ -65,9 +72,15 @@ while shiftopt; do
 		--no-follow)                   OPT_FOLLOW=false;;
 		--no-snip)                     OPT_SNIP="";;
 		--no-highlight)                OPT_HIGHLIGHT=false;;
+		--color)                       OPT_COLOR=true;;
+		--no-color)                    OPT_COLOR=false;;
 
 		# ???
 		-*) {
+			if pager_shiftopt; then
+				continue
+			fi
+
 			printc "%{RED}%s: unknown option '%s'%{CLEAR}\n" "$PROGRAM" "$OPT" 1>&2
 			exit 1
 		};;
@@ -88,16 +101,22 @@ if [[ -z "$PATTERN" ]]; then
 	exit 1
 fi
 
+# Append ripgrep and bat arguments.
 if "$OPT_FOLLOW"; then
 	RG_ARGS+=("--follow")	
 fi
 
+if "$OPT_COLOR"; then
+	BAT_ARGS+=("--color=always")
+fi
+
 if [[ "$OPT_CONTEXT_BEFORE" -eq 0 && "$OPT_CONTEXT_AFTER" -eq 0 ]]; then
 	OPT_SNIP=""
 	OPT_HIGHLIGHT=false
 fi
 
-# Invoke ripgrep.
+# Declare the main function.
+main() {
 	FOUND_FILES=()
 	FOUND=0
 	FIRST_PRINT=true
@@ -148,4 +167,8 @@ do_print
 	if [[ "$FOUND" -eq 0 ]]; then
 		exit 2
 	fi
+}
+
+# Execute main function with pager.
+pager_exec main