add bare word/number parsing

parse/parse.go

@@ -39,3 +39,56 @@ func ReadString(r io.Reader) (types.Str, error) {
 	}
 	return types.Str(ret), nil
 }
+
+
+// Returns (isNumber, isFloat). Can never return (false, true)
+func whatNumber(el string) (bool, bool) {
+	var isFloat bool
+	first := el[0]
+
+	var start int
+	if first == '-' {
+		if len(el) == 1 {
+			return false, false
+		}
+		start = 1
+	}
+
+	el = el[start:]
+	for i := range el {
+		if el[i] == '.' {
+			isFloat = true
+		} else if el[i] < '0' || el[i] > '9' {
+			return false, false
+		}
+	}
+
+	return true, isFloat
+}
+
+// Given a string with no spaces and with a length >= 1, parses it into either a
+// number or string.
+func ParseBareElement(el string) (types.Elem, error) {
+	isNumber, isFloat := whatNumber(el)
+	if isNumber {
+		if isFloat {
+			f, err := strconv.ParseFloat(el, 64)
+			if err != nil {
+				return nil, err
+			}
+			return types.Float(f), nil
+		} else {
+			i, err := strconv.ParseInt(el, 10, 64)
+			if err != nil {
+				return nil, err
+			}
+			return types.Int(i), nil
+		}
+	}
+
+	if el[0] == ':' {
+		return types.Str(el), nil
+	}
+
+	return types.Str(":"+el), nil
+}

parse/parse_test.go

@@ -28,3 +28,31 @@ func TestReadString(t *T) {
 		}
 	}
 }
+
+func TestParseBareElement(t *T) {
+	m := map[string]types.Elem{
+		`1`: types.Int(1),
+		`12`: types.Int(12),
+		`-1`: types.Int(-1),
+		`-12`: types.Int(-12),
+
+		`1.0`: types.Float(1.0),
+		`12.5`: types.Float(12.5),
+		`-12.5`: types.Float(-12.5),
+
+		`-`: types.Str(":-"),
+
+		`bare`: types.Str(":bare"),
+		`:not-bare`: types.Str(":not-bare"),
+	}
+
+	for input, output := range m {
+		el, err := ParseBareElement(input)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if output != el {
+			t.Fatalf("`%s` != `%s`", output, el)
+		}
+	}
+}

types/types.go

@@ -6,6 +6,10 @@ package types
 type Elem interface {
 }
 
+// Number can either be either an Int or a Float
+type Number interface {
+}
+
 type Str string
 
 type Int int