parse stdin (with a flag)

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "merlin"
-version = "1.3.5"
+version = "1.3.6"
 authors = ["geremachek <[email protected]>"]
 edition = "2018"
 

src/error.rs

@@ -1,4 +1,5 @@
 use std::fmt;
+use crate::util::ERROR_PREFIX;
 
 // our error structure
 
@@ -33,6 +34,6 @@ impl fmt::Display for MerlinError {
 			MerlinError::UnknownNomen          => "unknown nomen",
 		};
 
-		write!(f, "merlin: {}", msg)	
+		write!(f, "{} {}", ERROR_PREFIX, msg)	
 	}
 }

src/main.rs

@@ -21,6 +21,10 @@ fn main() {
 			.short("i")
 			.long("interrupt")
 			.help("Don't Block interrupts (Ctrl-C)"))
+		.arg(Arg::with_name("stdin")
+			.short("s")
+			.long("stdin")
+			.help("Parse stdin as merlin notation"))
 		.arg(Arg::with_name("NOTATION")
 			.index(1)
 			.multiple(true)
@@ -41,7 +45,13 @@ fn main() {
 		util::err_msg(ctrlc::set_handler(|| ()), "can't handle Ctrl-C events");
 	}
 
-	// start the shell
+	// check to see if we should parse stdin...
+
+	if merlin_args.is_present("stdin") {
+		p.parse_stdin()
+	}
+
+	// otherwise start the REPL
 
 	p.repl();
 }

src/plane/input.rs

@@ -1,6 +1,14 @@
 use crate::util;
 use super::{Plane, Vision};
-use std::io::{self, Write};
+use std::io::{self, Write, BufRead};
+
+// flush stdout, handling errors
+
+macro_rules! flush_stdout {
+	() => {
+		util::err_msg(io::stdout().flush(), "unable to flush stdout")
+	}
+}
 
 impl Plane {
 	pub fn repl(&mut self) {
@@ -14,16 +22,29 @@ impl Plane {
 				Vision::Scribe => self.parse_line(";scribe-prompt"),
 			};
 
-			util::err_msg(io::stdout().flush(), "unable to flush stdout");          // flush stdout, handling any errors
-			util::err_msg(io::stdin().read_line(&mut input), "unable to readline"); // read a line of input (handle any errors)
+			flush_stdout!();                                                         // flush stdout, handling any errors
+			util::err_msg(io::stdin().read_line(&mut input), "unable to read line"); // read a line of input (handle any errors)
 
 			// parse our line, stripping newlines
 
 			self.parse_line(strip_nl(&input));
 
 			input.clear();
 		}
-	} 
+	}
+
+	pub fn parse_stdin(&mut self) {
+		for line in io::stdin().lock().lines() {
+			self.parse_line(strip_nl(&line
+				.expect(&format!("{} {}", util::ERROR_PREFIX, "can't read stdin"))));
+
+			flush_stdout!();
+
+			if !self.running {
+				break;
+			}
+		}
+	}
 }
 
 // strip newlines

src/util.rs

@@ -1,7 +1,9 @@
 // print a nice error message on an error event
 
+pub const ERROR_PREFIX: &str = "merlin:";
+
 pub fn err_msg<T, E>(res: Result<T, E>, msg: &str) {
 	if let Err(_) = res {
-		eprintln!("merlin: {}", msg);
+		eprintln!("{} {}", ERROR_PREFIX, msg);
 	}
 }