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|
package common
import (
"strconv"
"strings"
"text/scanner"
"github.com/graph-gophers/graphql-go/errors"
)
type Literal interface {
Value(vars map[string]interface{}) interface{}
String() string
Location() errors.Location
}
type BasicLit struct {
Type rune
Text string
Loc errors.Location
}
func (lit *BasicLit) Value(vars map[string]interface{}) interface{} {
switch lit.Type {
case scanner.Int:
value, err := strconv.ParseInt(lit.Text, 10, 32)
if err != nil {
panic(err)
}
return int32(value)
case scanner.Float:
value, err := strconv.ParseFloat(lit.Text, 64)
if err != nil {
panic(err)
}
return value
case scanner.String:
value, err := strconv.Unquote(lit.Text)
if err != nil {
panic(err)
}
return value
case scanner.Ident:
switch lit.Text {
case "true":
return true
case "false":
return false
default:
return lit.Text
}
default:
panic("invalid literal")
}
}
func (lit *BasicLit) String() string {
return lit.Text
}
func (lit *BasicLit) Location() errors.Location {
return lit.Loc
}
type ListLit struct {
Entries []Literal
Loc errors.Location
}
func (lit *ListLit) Value(vars map[string]interface{}) interface{} {
entries := make([]interface{}, len(lit.Entries))
for i, entry := range lit.Entries {
entries[i] = entry.Value(vars)
}
return entries
}
func (lit *ListLit) String() string {
entries := make([]string, len(lit.Entries))
for i, entry := range lit.Entries {
entries[i] = entry.String()
}
return "[" + strings.Join(entries, ", ") + "]"
}
func (lit *ListLit) Location() errors.Location {
return lit.Loc
}
type ObjectLit struct {
Fields []*ObjectLitField
Loc errors.Location
}
type ObjectLitField struct {
Name Ident
Value Literal
}
func (lit *ObjectLit) Value(vars map[string]interface{}) interface{} {
fields := make(map[string]interface{}, len(lit.Fields))
for _, f := range lit.Fields {
fields[f.Name.Name] = f.Value.Value(vars)
}
return fields
}
func (lit *ObjectLit) String() string {
entries := make([]string, 0, len(lit.Fields))
for _, f := range lit.Fields {
entries = append(entries, f.Name.Name+": "+f.Value.String())
}
return "{" + strings.Join(entries, ", ") + "}"
}
func (lit *ObjectLit) Location() errors.Location {
return lit.Loc
}
type NullLit struct {
Loc errors.Location
}
func (lit *NullLit) Value(vars map[string]interface{}) interface{} {
return nil
}
func (lit *NullLit) String() string {
return "null"
}
func (lit *NullLit) Location() errors.Location {
return lit.Loc
}
type Variable struct {
Name string
Loc errors.Location
}
func (v Variable) Value(vars map[string]interface{}) interface{} {
return vars[v.Name]
}
func (v Variable) String() string {
return "$" + v.Name
}
func (v *Variable) Location() errors.Location {
return v.Loc
}
func ParseLiteral(l *Lexer, constOnly bool) Literal {
loc := l.Location()
switch l.Peek() {
case '$':
if constOnly {
l.SyntaxError("variable not allowed")
panic("unreachable")
}
l.ConsumeToken('$')
return &Variable{l.ConsumeIdent(), loc}
case scanner.Int, scanner.Float, scanner.String, scanner.Ident:
lit := l.ConsumeLiteral()
if lit.Type == scanner.Ident && lit.Text == "null" {
return &NullLit{loc}
}
lit.Loc = loc
return lit
case '-':
l.ConsumeToken('-')
lit := l.ConsumeLiteral()
lit.Text = "-" + lit.Text
lit.Loc = loc
return lit
case '[':
l.ConsumeToken('[')
var list []Literal
for l.Peek() != ']' {
list = append(list, ParseLiteral(l, constOnly))
}
l.ConsumeToken(']')
return &ListLit{list, loc}
case '{':
l.ConsumeToken('{')
var fields []*ObjectLitField
for l.Peek() != '}' {
name := l.ConsumeIdentWithLoc()
l.ConsumeToken(':')
value := ParseLiteral(l, constOnly)
fields = append(fields, &ObjectLitField{name, value})
}
l.ConsumeToken('}')
return &ObjectLit{fields, loc}
default:
l.SyntaxError("invalid value")
panic("unreachable")
}
}
|
