104 lines
2.0 KiB
Go
104 lines
2.0 KiB
Go
package objects
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import (
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"strconv"
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"github.com/d5/tengo"
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"github.com/d5/tengo/compiler/token"
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)
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// String represents a string value.
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type String struct {
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Value string
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runeStr []rune
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}
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// TypeName returns the name of the type.
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func (o *String) TypeName() string {
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return "string"
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}
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func (o *String) String() string {
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return strconv.Quote(o.Value)
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}
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// BinaryOp returns another object that is the result of
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// a given binary operator and a right-hand side object.
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func (o *String) BinaryOp(op token.Token, rhs Object) (Object, error) {
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switch op {
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case token.Add:
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switch rhs := rhs.(type) {
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case *String:
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if len(o.Value)+len(rhs.Value) > tengo.MaxStringLen {
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return nil, ErrStringLimit
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}
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return &String{Value: o.Value + rhs.Value}, nil
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default:
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rhsStr := rhs.String()
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if len(o.Value)+len(rhsStr) > tengo.MaxStringLen {
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return nil, ErrStringLimit
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}
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return &String{Value: o.Value + rhsStr}, nil
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}
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}
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return nil, ErrInvalidOperator
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}
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// IsFalsy returns true if the value of the type is falsy.
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func (o *String) IsFalsy() bool {
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return len(o.Value) == 0
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}
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// Copy returns a copy of the type.
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func (o *String) Copy() Object {
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return &String{Value: o.Value}
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}
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// Equals returns true if the value of the type
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// is equal to the value of another object.
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func (o *String) Equals(x Object) bool {
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t, ok := x.(*String)
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if !ok {
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return false
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}
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return o.Value == t.Value
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}
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// IndexGet returns a character at a given index.
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func (o *String) IndexGet(index Object) (res Object, err error) {
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intIdx, ok := index.(*Int)
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if !ok {
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err = ErrInvalidIndexType
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return
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}
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idxVal := int(intIdx.Value)
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if o.runeStr == nil {
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o.runeStr = []rune(o.Value)
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}
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if idxVal < 0 || idxVal >= len(o.runeStr) {
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res = UndefinedValue
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return
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}
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res = &Char{Value: o.runeStr[idxVal]}
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return
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}
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// Iterate creates a string iterator.
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func (o *String) Iterate() Iterator {
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if o.runeStr == nil {
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o.runeStr = []rune(o.Value)
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}
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return &StringIterator{
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v: o.runeStr,
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l: len(o.runeStr),
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}
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}
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