/
funcs.go
158 lines (150 loc) · 6.23 KB
/
funcs.go
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// Copyright 2021 Josh Deprez
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package yarn
import (
"fmt"
"math"
"math/big"
"math/rand"
)
// FuncMap maps function names to implementations. It is similar to the
// text/template FuncMap.
//
// Each function must return either 0, 1, or 2 values, and if 2 are returned,
// the latter must be type `error`.
//
// If the arguments being passed by the program are not assignable to an
// argument, and the argument has type bool, int, float32, float64, or string,
// then a conversion is attempted by the VM. For example, if the stack has the
// values ("3", true, 2) on top, CALL_FUNC with "Number.Add" (see below) would
// cause Number.Add's implementation to be called with (3.0, 1.0) (the 2 is the
// argument count).
type FuncMap map[string]interface{}
// merge merges fm into m and returns m.
func (m FuncMap) merge(fm FuncMap) FuncMap {
for n, f := range fm {
m[n] = f
}
return m
}
// defaultFuncMap returns a FuncMap with the standard Yarn Spinner operators.
func defaultFuncMap() FuncMap {
return FuncMap{
// --- Non-method funcs (old skool) ---
"None": func(x interface{}) interface{} { return x },
"EqualTo": func(x, y interface{}) bool { return x == y },
"NotEqualTo": func(x, y interface{}) bool { return x != y },
"GreaterThan": func(x, y float32) bool { return x > y },
"GreaterThanOrEqualTo": func(x, y float32) bool { return x >= y },
"LessThan": func(x, y float32) bool { return x < y },
"LessThanOrEqualTo": func(x, y float32) bool { return x <= y },
"Or": func(x, y bool) bool { return x || y },
"And": func(x, y bool) bool { return x && y },
"Xor": func(x, y bool) bool { return x != y },
"Not": func(x bool) bool { return !x },
"UnaryMinus": func(x float32) float32 { return -x },
// Add can't use implicit conversion, because it does something
// different depending on the argument types.
"Add": funcAdd,
"Minus": func(x, y float32) float32 { return x - y },
"Multiply": func(x, y float32) float32 { return x * y },
"Divide": func(x, y float32) float32 { return x / y },
"Modulo": func(x, y int) float32 { return float32(x % y) },
// --- Method funcs (2.0) ---
"Bool.EqualTo": func(x, y bool) bool { return x == y },
"Bool.NotEqualTo": func(x, y bool) bool { return x != y },
"Bool.Or": func(x, y bool) bool { return x || y },
"Bool.And": func(x, y bool) bool { return x && y },
"Bool.Xor": func(x, y bool) bool { return x != y },
"Bool.Not": func(x bool) bool { return !x },
"Number.EqualTo": func(x, y float32) bool { return x == y },
"Number.NotEqualTo": func(x, y float32) bool { return x != y },
"Number.Add": func(x, y float32) float32 { return x + y },
"Number.Minus": func(x, y float32) float32 { return x - y },
"Number.Multiply": func(x, y float32) float32 { return x * y },
"Number.Divide": func(x, y float32) float32 { return x / y },
"Number.Modulo": func(x, y int) float32 { return float32(x % y) },
"Number.UnaryMinus": func(x float32) float32 { return -x },
"Number.GreaterThan": func(x, y float32) bool { return x > y },
"Number.GreaterThanOrEqualTo": func(x, y float32) bool { return x >= y },
"Number.LessThan": func(x, y float32) bool { return x < y },
"Number.LessThanOrEqualTo": func(x, y float32) bool { return x <= y },
"String.EqualTo": func(x, y string) bool { return x == y },
"String.NotEqualTo": func(x, y string) bool { return x != y },
"String.Add": func(x, y string) string { return x + y },
// built-in functions from documentation.
"random": func() float32 { return rand.Float32() },
"random_range": func(x, y int) float32 { return float32(rand.Intn(y-x) + x) },
"dice": func(x int) float32 { return float32(rand.Intn(x) + 1) },
"round": func(x float32) float32 { return float32(math.Round(float64(x))) },
"round_places": func(n float32, places uint) float32 {
f := new(big.Float).SetMode(big.ToNearestEven).SetPrec(places).SetFloat64(float64(n))
result, _ := f.Float32()
return result
},
"floor": func(n float32) float32 { return float32(math.Floor(float64(n))) },
"ceil": func(n float32) float32 { return float32(math.Ceil(float64(n))) },
"inc": func(n float32) float32 { return float32(math.Trunc(float64(n)) + 1) },
"dec": func(n float32) float32 { return float32(math.Ceil(float64(n)) - 1) },
"decimal": func(n float32) float32 { _, f := math.Modf(float64(n)); return float32(f) },
}
}
func funcAdd(x, y interface{}) (interface{}, error) {
if x == nil {
return y, nil
}
if y == nil {
return x, nil
}
// Try strings first
if xt, ok := x.(string); ok {
return xt + ConvertToString(y), nil
}
if yt, ok := y.(string); ok {
return ConvertToString(x) + yt, nil
}
// numeric, probably
switch xt := x.(type) {
case bool:
// upconvert both to numbers
xtt, err := ConvertToFloat32(x)
if err != nil {
return nil, err
}
yt, err := ConvertToFloat32(y)
if err != nil {
return nil, err
}
return xtt + yt, nil
case float32:
yt, err := ConvertToFloat32(y)
if err != nil {
return nil, err
}
return xt + yt, nil
case float64:
yt, err := ConvertToFloat64(y)
if err != nil {
return nil, err
}
return xt + yt, nil
case int:
yt, err := ConvertToInt(y)
if err != nil {
return nil, err
}
return xt + yt, nil
}
return false, fmt.Errorf("unsupported type [%T ∉ {nil,bool,float32,float64,int,string}]", x)
}