added custom flag parser

fleg/flag.odin

@@ -0,0 +1,162 @@
+#+vet explicit-allocators
+package fleg
+
+import "base:runtime"
+import "core:fmt"
+import "core:os"
+import "core:strconv"
+import "core:strings"
+
+FORCE_HELP_ON_EMPTY_ARGS := false
+
+Flag_Value_Ptr :: union {
+	^bool,
+	^int,
+	^string,
+	^f32,
+	^f64,
+}
+
+Flag :: struct {
+	name:   string,
+	value:  Flag_Value_Ptr,
+	usage:  string,
+	parsed: bool, // sck: flag to check if it has been parsed
+}
+
+all_flags: [dynamic]Flag
+flag_allocator: runtime.Allocator
+
+// sck: Used to create a customer allocator
+init_custom_allocator :: proc(allocator: runtime.Allocator) {
+	destroy() // sck: make sure to destory the old allocations
+
+	flag_allocator = allocator
+	all_flags = make([dynamic]Flag, flag_allocator)
+}
+
+destroy :: proc() {
+	delete(all_flags)
+	all_flags = {} // sck: needed?
+}
+
+print_flags :: proc() {
+	for f in all_flags {
+		fmt.printfln("%s: %v: %s", f.name, f.value, f.usage)
+	}
+}
+
+print_usage :: proc() {
+	fmt.println("\tUsage: ")
+	for f in all_flags {
+		switch v in f.value {
+		case ^bool:
+			fmt.printfln("\t-%s:\n\t\t%s (default: %v)\n", f.name, f.usage, v^)
+		case ^int:
+			fmt.printfln("\t-%s:\n\t\t%s (default: %d)\n", f.name, f.usage, v^)
+		case ^string:
+			fmt.printfln("\t-%s:\n\t\t%s (default: %s)\n", f.name, f.usage, v^)
+		case ^f32:
+			fmt.printfln("\t-%s:\n\t\t%s (default: %f)\n", f.name, f.usage, v^)
+		case ^f64:
+			fmt.printfln("\t-%s:\n\t\t%s (default: %f)\n", f.name, f.usage, v^)
+		}
+	}
+	os.exit(0)
+}
+
+BoolVar :: proc(ptr: ^bool, name: string, default: bool, usage: string) {
+	ptr^ = default
+	append(&all_flags, Flag{name = name, value = ptr, usage = usage})
+}
+
+IntVar :: proc(ptr: ^int, name: string, default: int, usage: string) {
+	ptr^ = default
+	append(&all_flags, Flag{name = name, value = ptr, usage = usage})
+}
+
+StringVar :: proc(ptr: ^string, name: string, default: string, usage: string) {
+	ptr^ = default
+	append(&all_flags, Flag{name = name, value = ptr, usage = usage})
+}
+
+Float32Var :: proc(ptr: ^f32, name: string, default: f32, usage: string) {
+	ptr^ = default
+	append(&all_flags, Flag{name = name, value = ptr, usage = usage})
+}
+
+Float64Var :: proc(ptr: ^f64, name: string, default: f64, usage: string) {
+	ptr^ = default
+	append(&all_flags, Flag{name = name, value = ptr, usage = usage})
+}
+
+parse_flags :: proc() {
+	if len(os.args) < 2 && FORCE_HELP_ON_EMPTY_ARGS {print_usage()}
+
+	for &a in os.args {
+		if a == "-help" || a == "--help" {print_usage()}
+		if a == os.args[0] {continue}
+
+		for &f in all_flags {
+			if f.parsed {continue}
+			a = strings.trim_prefix(a, "-")
+
+			name := a
+			value: string
+
+			split := strings.index_any(a, "=")
+			if split >= 0 {
+				name = a[:split]
+				value = a[split + 1:]
+			} else {
+				name = a
+			}
+
+			if name == f.name && !f.parsed {
+				f.parsed = true
+				switch &v in f.value {
+				case ^bool:
+					if value == "" {break}
+					parsed, ok := strconv.parse_bool(value)
+					if !ok {
+						fmt.fprintfln(os.stderr, "[ERROR] Failed to parse flag %s: got %T, wanted bool", f.name, value)
+						os.exit(1)
+					}
+					v^ = parsed
+
+				case ^int:
+					if value == "" {break}
+					parsed, ok := strconv.parse_int(value)
+					if !ok {
+						fmt.fprintfln(os.stderr, "[ERROR] Failed to parse flag %s: got %T, wanted int", f.name, value)
+						os.exit(1)
+					}
+					v^ = parsed
+
+				case ^string:
+					if value == "" {break}
+					// TODO: validate string?
+					v^ = value
+
+				case ^f32:
+					if value == "" {break}
+					parsed, ok := strconv.parse_f32(value)
+					if !ok {
+						fmt.fprintfln(os.stderr, "[ERROR] Failed to parse flag %s: got %T, wanted f32", f.name, value)
+						os.exit(1)
+					}
+					v^ = parsed
+
+				case ^f64:
+					if value == "" {break}
+					parsed, ok := strconv.parse_f64(value)
+					if !ok {
+						fmt.fprintfln(os.stderr, "[ERROR] Failed to parse flag %s: got %T, wanted f64", f.name, value)
+						os.exit(1)
+					}
+					v^ = parsed
+				}
+			}
+		}
+	}
+}

main.odin

@@ -3,6 +3,7 @@ package main
 
 import "core:fmt"
 import "core:os"
+import "fleg"
 import SDL "vendor:sdl2"
 
 WINDOW_TITLE :: "PPM Viewer"
@@ -18,14 +19,23 @@ print_usage :: proc() {
 }
 
 main :: proc() {
+	/*
 	if len(os.args) > 3 || len(os.args) < 2 {
 		print_usage()
 	}
+  */
 
 	file := Ppm_file{}
-	filename := os.args[1]
+
-	if ok, err := load_ppm(&file, filename, context.temp_allocator); !ok {
+	file_arg: string
-		fmt.eprintfln("ERROR: Failed to load file '%s': %s ", filename, os.error_string(err))
+	fleg.StringVar(&file_arg, "f", "in.ppm", "input file [.ppm]")
+	fleg.FORCE_HELP_ON_EMPTY_ARGS = true
+	defer fleg.destroy()
+
+	fleg.parse_flags()
+
+	if ok, err := load_ppm(&file, file_arg, context.temp_allocator); !ok {
+		fmt.eprintfln("ERROR: Failed to load file '%s': %s ", file_arg, os.error_string(err))
 		os.exit(1)
 	}
 	ppm_parse(&file, context.temp_allocator)