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120 | package evaluator
import (
"mana/object"
)
var builtins = map[string]*object.Builtin{
"len": {
Fn: func(args ...object.Object) object.Object {
if len(args) != 1 {
return newError("wrong number of arguments. got=%d, want=1",
len(args))
}
switch arg := args[0].(type) {
case *object.String:
return &object.Integer{Value: int64(len(arg.Value))}
case *object.Array:
return &object.Integer{Value: int64(len(arg.Elements))}
default:
return newError("argument to `len` not supported, got %s", arg.Type())
}
},
},
"first": {
Fn: func(args ...object.Object) object.Object {
if len(args) != 1 {
return newError("wrong number of arguments. got=%d, want=1",
len(args))
}
if args[0].Type() != object.ARRAY_OBJ {
return newError("argument to `first` must be ARRAY, got %s",
args[0].Type())
}
arr := args[0].(*object.Array)
if len(arr.Elements) > 0 {
return arr.Elements[0]
}
return NULL
},
},
"last": {
Fn: func(args ...object.Object) object.Object {
if len(args) != 1 {
return newError("wrong number of arguments. got=%d, want=1",
len(args))
}
if args[0].Type() != object.ARRAY_OBJ {
return newError("argument to `last` must be ARRAY, got %s",
args[0].Type())
}
arr := args[0].(*object.Array)
length := len(arr.Elements)
if length > 0 {
return arr.Elements[length-1]
}
return NULL
},
},
"rest": {
Fn: func(args ...object.Object) object.Object {
if len(args) != 1 {
return newError("wrong number of arguments. got=%d, want=1",
len(args))
}
if args[0].Type() != object.ARRAY_OBJ {
return newError("argument to `rest` must be ARRAY, got %s",
args[0].Type())
}
arr := args[0].(*object.Array)
length := len(arr.Elements)
if length > 0 {
newElements := make([]object.Object, length-1)
copy(newElements, arr.Elements[1:length])
return &object.Array{Elements: newElements}
}
return NULL
},
},
"push": {
Fn: func(args ...object.Object) object.Object {
if len(args) != 2 {
return newError("wrong number of arguments. got=%d, want=2",
len(args))
}
if args[0].Type() != object.ARRAY_OBJ {
return newError("argument to `push` must be ARRAY, got %s",
args[0].Type())
}
arr := args[0].(*object.Array)
length := len(arr.Elements)
newElements := make([]object.Object, length+1)
copy(newElements, arr.Elements)
newElements[length] = args[1]
return &object.Array{Elements: newElements}
},
},
"puts": {
Fn: func(args ...object.Object) object.Object {
for _, arg := range args {
println(arg.Inspect())
}
return NULL
},
},
}
|
