@@ -58,3 +58,3 @@
 
 libgetopt: src/getopt-rs/lib.rs
-	$(RUSTC) $(RUSTCFLAGS) --crate-type=lib --crate-name=getopt \
+	$(RUSTC) $(RUSTFLAGS) --crate-type=lib --crate-name=getopt \

@@ -0,0 +69,4 @@
+}
+
+#[derive(Debug, Clone)]
+struct EvaluationError {

@@ -0,0 +85,4 @@
+
+// str_to_calc_type converts a string to an optional `CalcType`.
+fn str_to_calc_type(string: &str) -> Option<CalcType> {
+	let as_int = string.parse::<f64>();

@@ -0,0 +106,4 @@
+	}
+}
+
+fn eval(

@@ -0,0 +132,4 @@
+		};
+
+		match x {
+			Add | Divide | Multiply | Power | Subtract | Modulo => {

@@ -0,0 +156,4 @@
+					Multiply => &stack.push_back(y * x),
+					Divide => &stack.push_back(y / x),
+					Power => &stack.push_back(x.powf(*y)),
+					Modulo => &stack.push_back(y % x),

@@ -0,0 +183,4 @@
+	let argv = args().collect::<Vec<String>>();
+	let mut stack = VecDeque::new();
+	let mut buf = String::new();
+	let precision = (-f64::EPSILON.log10() * PRECISION_MOD).ceil() as usize;

@@ -0,0 +7,4 @@
+
+.SH NAME
+
+npc \(en reverse polish notation evaluation

@@ -0,0 +11,4 @@
+
+.SH SYNOPSIS
+
+rpn [integers...] [operations...]

@@ -0,0 +13,4 @@
+
+rpn [integers...] [operations...]
+
+.SH DESCRIPTION

@@ -0,0 +22,4 @@
+.SH STANDARD INPUT
+
+If rpn is passed arguments, it interprets those arguments as an expression to
+be evaluated. Otherwise, it reads characters from standard input to add to the

@@ -0,0 +33,4 @@
+.SH CAVEATS
+
+Due to the complexity of integer storage in memory, rpn is only capable of
+parsing decimal integers.

@@ -0,0 +37,4 @@
+
+Additionally, due to the laws of physics, floating-point math can only be as
+precise as slightly less than the machine epsilon of the hardware on which rpn
+is running.

@@ -0,0 +43,4 @@
+
+POSIX has its own calculator in the form of bc(1p), which uses standard input
+for its calculations. Pair the clunkiness of piping expressions into it and its
+use of standard notation, it was clear what rpn should be.

@@ -0,0 +47,4 @@
+
+There are no mathematics in the qi(1) shell because it was decided early on that
+math was the job of a specific tool and not the shell itself. Thus, rpn was
+born.

@@ -0,0 +68,4 @@
+	Modulo,
+	Val(f64),
+	Empty,
+}

@@ -0,0 +77,4 @@
+			"-" | "−" => Subtract,
+			"*" | "×" => Multiply,
+			"/" | "÷" => Divide,
+			"^" => Power,

@@ -0,0 +148,4 @@
+			Val(v) => stack.push_back(v),
+			Invalid => {
+				return Err(EvaluationError {
+					message: format!("{}: Invalid token", n)

@@ -0,0 +18,4 @@
+.SH DESCRIPTION
+
+Rpn parses and and evaluates reverse polish notation expressions either from the
+standard input or by parsing its arguments. See the STANDARD INPUT section.

@@ -0,0 +22,4 @@
+
+Upon evaluation, rpn will print the resulting number on the stack to the
+standard output. Any further specified numbers will be placed on the stack
+following the last outputted number.

@@ -0,0 +28,4 @@
+
+.SH STANDARD INPUT
+
+If rpn is passed arguments, it interprets them as an expression to be evaluated.

@@ -0,0 +43,4 @@
+with the IEEE Standard for Floating Point Arithmetic (IEEE 754), floating-point
+arithmetic has rounding errors. This is somewhat curbed by using the
+second-highest float that can be represented in line with this standard to round
+numbers to before outputting.

@@ -0,0 +48,4 @@
+.SH RATIONALE
+
+An infix notation calculation utility, bc(1p), is included in the POSIX
+standard, but it doesn’t accept expressions as arguments; in scripts, any

@@ -0,0 +99,4 @@
+			Multiply => "multiplication",
+			Divide => "division",
+			Power => "exponentiation",
+			Floor => "floor divion",