Add bash completion

Author: 8dcc

Makefile

@@ -7,23 +7,30 @@ SRC=main.c args.c byte_array.c image.c util.c file.c generate_ascii.c generate_b
 OBJ=$(addprefix obj/, $(addsuffix .o, $(SRC)))
 
 BIN=bin-graph
+COMPLETION=bin-graph-completion.bash
 
 PREFIX=/usr/local
 BINDIR=$(PREFIX)/bin
+COMPLETIONDIR=$(PREFIX)/share/bash-completion/completions
 
 #-------------------------------------------------------------------------------
 
-.PHONY: all clean install
+.PHONY: all clean install install-bin install-completion
 
 all: $(BIN)
 
 clean:
 	rm -f $(OBJ)
 	rm -f $(BIN)
 
-install: $(BIN)
+install: install-bin install-completion
+
+install-bin: $(BIN)
 	install -D -m 755 $^ -t $(DESTDIR)$(BINDIR)
 
+install-completion: $(COMPLETION)
+	install -D -m 644 $^ $(DESTDIR)$(COMPLETIONDIR)/$(BIN)
+
 #-------------------------------------------------------------------------------
 
 $(BIN): $(OBJ)

bin-graph-completion.bash

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+
+_bin_graph_completion() {
+    local arg_opts nonarg_opts
+    arg_opts=(
+        -m --mode
+        -w --width
+        -z --zoom
+        --block-size
+        --offset-start --offset-end
+        --output-format
+        --transform-squares
+    )
+    nonarg_opts=(
+        -h --help
+        --list-modes
+        --list-output-formats
+    )
+
+    # If the previous option ('$3') is a redirector, show the default file
+    # completion.
+    if [[ "$3" == '2>' || "$3" == '>' || "$3" == '<' ]]; then
+        compopt -o bashdefault -o default
+        return
+    fi
+
+    # If the previous option expected an extra parameter, don't show completion.
+    for arg in "${arg_opts[@]}"; do
+        if [ "$3" = "$arg" ]; then
+            return
+        fi
+    done
+
+    if [[ "$2" = -* ]]; then
+        # If the current option ('$2') starts with a dash, return (in
+        # '$COMPREPLY') the possible completions for the current option using
+        # 'compgen'.
+        mapfile -t COMPREPLY < <(compgen -W "${arg_opts[*]} ${nonarg_opts[*]}" -- "$2")
+    else
+        # Otherwise, show the default file completion.
+        compopt -o bashdefault -o default
+    fi
+}
+
+complete -F _bin_graph_completion bin-graph