Initial Util Package

util/io.py

@@ -0,0 +1,32 @@
+#!/usr/bin/python3
+
+"""
+Input/Output utilities.
+"""
+
+import sys
+
+
+def readvalue(msg, type_, emsg=None, fin=sys.stdin, fout=sys.stdout):
+	"""
+	Basically uses ``input(msg)`` until it has been able to convert 
+	the input to ``type_``. Prints the error message ``emsg``
+	if supplied, else the type error message.
+
+	Reads from ``fin`` and writes to ``fout``. They default to ``sys.stdin``
+	and ``sys.stdout``.
+	"""
+	x = None
+	while(x is None):
+		print(msg, file=fout, flush=True, end="")
+		x_raw = fin.readline()
+		try:
+			# Remove the trailing \n.
+			x = type_(x_raw[:-1])
+		except ValueError as e:
+			if(emsg):
+				print(emsg, file=fout, flush=True)
+			else:
+				print(str(e), file=fout, flush=True)
+
+	return x