Created a bunch of tests for the parser, and a spec.

float_parser_tests.cc

@@ -0,0 +1,55 @@
+#include <cstdio>
+#include <cstddef>
+
+// Tries to parse a floating point number located at s.
+//
+// Parses the following EBNF grammar:
+//   sign    = "+" | "-" ;
+//   END     = ? anything not in digit ?
+//   digit   = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
+//   integer = [sign] , digit , {digit} ;
+//   decimal = integer , ["." , {digit}] ;
+//   float   = ( decimal , END ) | ( decimal , ("E" | "e") , decimal , END ) ;
+//
+//  Valid strings are for example:
+//   -0	 +3.1417e+2  -0.E-3  1.0324  -1.41   11e2
+//
+// If the parsing is a success, result is set to the parsed value and true 
+// is returned.
+//
+// The function is greedy, it will parse until it encounters a null-byte or
+// a non-conforming character is encountered.
+//
+// The following situations triggers a failure:
+//  - parse failure.
+//  - underflow/overflow.
+// 
+bool tryParseFloat(const char *s, double *result)
+{
+	return false;
+}
+
+void testParsing(const char *input, bool expectedRes, double expectedValue)
+{
+	double val = 0.0;
+	bool res = tryParseFloat(input, &val);
+	if (res != expectedRes || val != expectedValue)
+	{
+		printf("% 20s failed, returned %d and value % 10.4f.\n", input, res, val);
+	}
+}
+
+int main(int argc, char const *argv[])
+{
+	testParsing("0",  true,  0.0);
+	testParsing("-0", true,  0.0);
+	testParsing("+0", true,  0.0);
+	testParsing("1",  true,  1.0);
+	testParsing("+1", true,  1.0);
+	testParsing("-1", true, -1.0);
+	testParsing("-1.08", true, -1.08);
+	testParsing("100.0823blabla", true, 100.0823);
+	testParsing("34.E-2\04", true, 34.0e-2);
+	testParsing("+34.23E2\02", true, 34.23E2);
+	return 0;
+}