generator_to_string.go

// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main

func (g *Generator) buildOneRunStringer(values []Value, typeName string) {
	// The generated code is simple enough to write as a Printf format.
	lessThanZero := ""
	if values[0].signed {
		lessThanZero = "i < 0 || "
	}

	if values[0].value == 0 { // Signed or unsigned, 0 is still 0.
		g.Printf(stringToStringOneRun, typeName, lessThanZero)
	} else {
		g.Printf(stringToStringOneRunWithOffset, typeName, values[0].String(), lessThanZero)
	}
}

// Arguments to format are:
//	[1]: type name
//	[2]: less than zero check (for signed types)
const stringToStringOneRun = `func (i %[1]s) String() string {
	if %[2]si >= %[1]s(len(_%[1]s_index)-1) {
		return "%[1]s(" + strconv.FormatInt(int64(i), 10) + ")"
	}
	return _%[1]s_name[_%[1]s_index[i]:_%[1]s_index[i+1]]
}
`

// Arguments to format are:
//	[1]: type name
//	[2]: lowest defined value for type, as a string
//	[3]: less than zero check (for signed types)
const stringToStringOneRunWithOffset = `func (i %[1]s) String() string {
	i -= %[2]s
	if %[3]si >= %[1]s(len(_%[1]s_index)-1) {
		return "%[1]s(" + strconv.FormatInt(int64(i + %[2]s), 10) + ")"
	}
	return _%[1]s_name[_%[1]s_index[i]:_%[1]s_index[i+1]]
}
`

func (g *Generator) buildMultipleRunsStringer(runs [][]Value, typeName string) {

	g.Printf("func (i %s) String() string {\n", typeName)
	g.Printf("\tswitch {\n")
	for i, values := range runs {
		if len(values) == 1 {
			g.Printf("\tcase i == %s:\n", &values[0])
			g.Printf("\t\treturn _%s_name_%d\n", typeName, i)
			continue
		}
		if values[0].value == 0 && !values[0].signed {
			// For an unsigned lower bound of 0, "0 <= i" would be redundant.
			g.Printf("\tcase i <= %s:\n", &values[len(values)-1])
		} else {
			g.Printf("\tcase %s <= i && i <= %s:\n", &values[0], &values[len(values)-1])
		}
		if values[0].value != 0 {
			g.Printf("\t\ti -= %s\n", &values[0])
		}
		g.Printf("\t\treturn _%s_name_%d[_%s_index_%d[i]:_%s_index_%d[i+1]]\n",
			typeName, i, typeName, i, typeName, i)
	}
	g.Printf("\tdefault:\n")
	g.Printf("\t\treturn \"%s(\" + strconv.FormatInt(int64(i), 10) + \")\"\n", typeName)
	g.Printf("\t}\n")
	g.Printf("}\n")
}

func (g *Generator) buildMapStringer(typeName string) {
	g.Printf(stringToStringMap, typeName)
}

// Argument to format is the type name.
const stringToStringMap = `func (i %[1]s) String() string {
	if str, ok := _%[1]s_map[i]; ok {
		return str
	}
	return "%[1]s(" + strconv.FormatInt(int64(i), 10) + ")"
}
`