refactored help flag and initial implementations of 'empty' and 'version' flags

src/flag.rs

@@ -0,0 +1,6 @@
+
+pub const EMPTY_CONTEXT:	[&str;2]	=	[ "-E", "--empty"];
+pub const HELP:				[&str;2]	=	[ "-h", "--help" ];
+pub const QUIET:			[&str;2]	=	[ "-q", "--quiet" ];
+pub const VERSION:			[&str;2]	=	[ "-V", "--version" ];
+

src/main.rs

@@ -21,6 +21,7 @@ use termion::{
 	style
 };
 
+mod flag;
 mod global;
 mod helper;
 mod util;
@@ -28,10 +29,22 @@ mod util;
 pub const VERSION: &str = env!("CARGO_PKG_VERSION");
 
 fn main() {
-	let args = Arguments::from_env();
+	let mut args = Arguments::from_env();
 
-	//	build eval context
-	let mut context = context_map! {
+	//	handle breaking flags
+	if args.contains(flag::HELP) {
+		help_text();
+		return;
+	}
+	if args.contains(flag::VERSION) {
+		version_text();
+		return;
+	}
+
+	//	build context and handle empty flag
+	let mut context =
+		if !args.contains(flag::EMPTY_CONTEXT) {
+			context_map! {
 				//	globals
 				"c"		=>	global::LIGHT_SPEED,
 				"e"		=>	global::EULER,
@@ -56,21 +69,22 @@ fn main() {
 				"ϕ"		=>	global::GOLDEN_RATIO,
 				"π"		=>	global::PI,
 				"√"		=>	Function::new(|arg| helper::square_root(arg))
-	}.unwrap();
+			}.unwrap()
+		} else {
+			HashMapContext::new()
+		};
 
 	//	collect args and evaluate if present
 	let expressions = args.finish();
 	if expressions.len() > 0 {
 		for expression in expressions {
 			let expression: String = expression.to_string_lossy().into();
-			match expression.as_str() {
-				"help"	=>	help_text(),
-				_		=>	do_eval(expression, &mut context)
-			}
+			do_eval(expression, &mut context)
 		}
 	} else {
 		//	enter interactive mode if no args are given
-		println!("{}quickmaths v{}{}\n{}Interactive Mode{}", style::Bold, VERSION, style::Reset, style::Faint, style::Reset);
+		version_text();
+		println!("{}Interactive Mode{}", style::Faint, style::Reset);
 		loop {
 			print!("> ");
 			stdout().flush().unwrap();
@@ -135,16 +149,17 @@ fn reset() {
 	stdout().flush().unwrap();
 }
 
+fn version_text() {
+	println!("qm v{VERSION}");
+}
+
 fn help_text() {
+	version_text();
 	println!(
-		"{bold}quickmaths v{version}{reset}
-Valerie Wolfe <sleeplessval@gmail.com>
+"Valerie Wolfe <sleeplessval@gmail.com>
 A mathematical expression evaluator written in Rust.
 
 usage:
-   qm [EXPRESSION]...",
-		bold = style::Bold,
-		reset = style::Reset,
-		version = crate::VERSION
+   qm [EXPRESSION]..."
 	);
 }