major main method cleanup and implemented quiet flag

src/main.rs

@@ -5,12 +5,14 @@ use std::{
 		stdout,
 
 		Write
-	}
+	},
+	process::exit
 };
 
 use evalexpr::{
 	eval_with_context_mut,
-	ContextWithMutableVariables,
+
+	EvalexprError,
 	HashMapContext,
 	Value
 };
@@ -21,7 +23,6 @@ use termion::{
 };
 
 mod context;
-mod eval;
 mod flag;
 mod util;
 
@@ -41,13 +42,14 @@ fn main() {
 	}
 
 	let mut context = util::build_context(&mut args);
+	let quiet = args.contains(flag::QUIET);
 
 	//	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();
-			do_eval(expression, &mut context)
+			eval(&expression, &mut context, quiet);
 		}
 	} else {
 		//	enter interactive mode if no args are given
@@ -65,44 +67,44 @@ fn main() {
 			match line.as_str() {
 				""		|
 				"exit"	=>	break,
-				_		=>	do_eval(line, &mut context)
+				_		=>	eval(&line, &mut context, quiet)
 			}
 			reset();
 		}
 	}
 }
 
-fn do_eval(i_expression: String, context: &mut HashMapContext) {
-	let expression = i_expression.as_str();
+fn eval(expression: &str, context: &mut HashMapContext, quiet: bool) {
 	let result = eval_with_context_mut(expression, context);
+	if quiet {
+		if let Ok(result) = result { println!("{result}") }
+		else { exit(1) }
+	} else { format(expression, result) }
+}
+
+fn format(expression: &str, result: Result<Value, EvalexprError>) {
 	if let Ok(result) = result {
-		//	display empty result
-		if result.is_empty() {
+		if !result.is_empty() {
+			let delimiter =
+				match result {
+					Value::Boolean(_)	=>	"is",
+					Value::String(_)	=>	"=>",
+					_					=>	"="
+				};
+			println!(
+				"{faint}{italic}{expression}{reset} {delimiter} {bold}{result}",
+				bold	=	style::Bold,
+				faint	=	style::Faint,
+				italic	=	style::Italic,
+				reset	=	style::Reset
+			);
+		} else {
 			println!(
 				"{green}✓ {bold}{expression}",
 				bold = style::Bold,
 				green = color::Fg(color::Green)
 			);
-			return;
 		}
-
-		//	get appropriate symbol for result by type
-		let delimiter;
-		match result {
-			Value::Boolean(_bool)		=>	delimiter = "is",
-			Value::String(ref _str)		=>	delimiter = "=>",
-			_							=>	delimiter = "="
-		}
-		println!(
-			"{faint}{italic}{expression}{reset} {delimiter} {bold}{result}",
-			bold = style::Bold,
-			faint = style::Faint,
-			italic = style::Italic,
-			reset = style::Reset
-		);
-
-		//	set "last" variable
-		context.set_value("$".to_string(), result).ok();
 	} else {
 		println!(
 			"{red}✕ {bold}{expression}",