Go: move the stdlib to a different file

This commit is contained in:
Přemysl Eric Janouch 2018-10-10 21:23:25 +02:00
parent 64f892f40e
commit c81f986ec2
Signed by: p
GPG Key ID: A0420B94F92B9493
2 changed files with 513 additions and 495 deletions

View File

@ -20,11 +20,6 @@ import (
"errors"
"fmt"
"io"
// standard library
"bytes"
"os"
"os/exec"
)
// --- Values ------------------------------------------------------------------
@ -717,493 +712,3 @@ func (ell *Ell) EvalBlock(body []V, args []V) (result []V, ok bool) {
ell.scopes = ell.scopes[:len(ell.scopes)-1]
return result, ok
}
// --- Standard library --------------------------------------------------------
// EvalAny evaluates any value and appends to the result.
func EvalAny(ell *Ell, body *V, arg *V) (result []V, ok bool) {
if body.Type == VTypeString {
return []V{*body}, true
}
var args []V
if arg != nil {
args = append(args, *arg.Clone())
}
if res, ok := ell.EvalBlock(body.List, args); ok {
return res, true
}
return nil, false
}
// NewNumber creates a new string value containing a number.
func NewNumber(n float64) *V {
s := fmt.Sprintf("%f", n)
i := len(s)
for i > 0 && s[i-1] == '0' {
i--
}
if s[i-1] == '.' {
i--
}
return NewString(s[:i])
}
// Truthy decides whether any value is logically true.
func Truthy(v *V) bool {
return v != nil && (len(v.List) > 0 || len(v.String) > 0)
}
// NewBoolean creates a new string value copying the boolean's truthiness.
func NewBoolean(b bool) *V {
if b {
return NewString("1")
}
return NewString("")
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
func fnLocal(ell *Ell, args []V) (result []V, ok bool) {
if len(args) == 0 || args[0].Type != VTypeList {
return ell.Errorf("first argument must be a list")
}
// Duplicates or non-strings don't really matter to us, user's problem.
scope := ell.scopes[len(ell.scopes)-1]
values := args[1:]
for _, name := range args[0].List {
if len(values) > 0 {
scope[name.String] = *values[0].Clone()
values = values[1:]
}
}
return nil, true
}
func fnSet(ell *Ell, args []V) (result []V, ok bool) {
if len(args) == 0 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
if len(args) > 1 {
result = []V{*args[1].Clone()}
ell.Set(args[0].String, &result[0])
return result, true
}
// We return an empty list for a nil value.
if v := ell.Get(args[0].String); v != nil {
result = []V{*v.Clone()}
} else {
result = []V{*NewList(nil)}
}
return result, true
}
func fnList(ell *Ell, args []V) (result []V, ok bool) {
return []V{*NewList(args)}, true
}
func fnValues(ell *Ell, args []V) (result []V, ok bool) {
return args, true
}
func fnIf(ell *Ell, args []V) (result []V, ok bool) {
var cond, body, keyword int
for cond = 0; ; cond = keyword + 1 {
if cond >= len(args) {
return ell.Errorf("missing condition")
}
if body = cond + 1; body >= len(args) {
return ell.Errorf("missing body")
}
var res []V
if res, ok = EvalAny(ell, &args[cond], nil); !ok {
return nil, false
}
if len(res) > 0 && Truthy(&res[0]) {
return EvalAny(ell, &args[body], nil)
}
if keyword = body + 1; keyword >= len(args) {
break
}
if args[keyword].Type != VTypeString {
return ell.Errorf("expected keyword, got list")
}
switch kw := args[keyword].String; kw {
case "else":
if body = keyword + 1; body >= len(args) {
return ell.Errorf("missing body")
}
return EvalAny(ell, &args[body], nil)
case "elif":
default:
return ell.Errorf("invalid keyword: %s", kw)
}
}
return nil, true
}
func fnMap(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 {
return ell.Errorf("first argument must be a function")
}
if len(args) < 2 || args[0].Type != VTypeList {
return ell.Errorf("second argument must be a list")
}
body, values := &args[0], &args[1]
for _, v := range values.List {
res, ok := EvalAny(ell, body, &v)
if !ok {
return nil, false
}
result = append(result, res...)
}
return []V{*NewList(result)}, true
}
func fnPrint(ell *Ell, args []V) (result []V, ok bool) {
for _, arg := range args {
if arg.Type != VTypeString {
PrintV(os.Stdout, &arg)
} else if _, err := os.Stdout.WriteString(arg.String); err != nil {
return ell.Errorf("write failed: %s", err)
}
}
return nil, true
}
func fnCat(ell *Ell, args []V) (result []V, ok bool) {
buf := bytes.NewBuffer(nil)
for _, arg := range args {
if arg.Type != VTypeString {
PrintV(buf, &arg)
} else {
buf.WriteString(arg.String)
}
}
return []V{*NewString(buf.String())}, true
}
func fnSystem(ell *Ell, args []V) (result []V, ok bool) {
var argv []string
for _, arg := range args {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
argv = append(argv, arg.String)
}
if len(argv) == 0 {
return ell.Errorf("command name required")
}
cmd := exec.Command(argv[0], argv[1:]...)
cmd.Stdin = os.Stdin
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
// Approximation of system(3) return value to match C ell at least a bit.
if err := cmd.Run(); err == nil {
return []V{*NewNumber(0)}, true
} else if _, ok := err.(*exec.Error); ok {
return ell.Errorf("%s", err)
} else {
return []V{*NewNumber(1)}, true
}
}
func fnParse(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
res, err := NewParser([]byte(args[0].String)).Run()
if err != nil {
return ell.Errorf("%s", err)
}
return []V{*NewList(res)}, true
}
func fnTry(ell *Ell, args []V) (result []V, ok bool) {
var body, handler *V
if len(args) < 1 {
return ell.Errorf("first argument must be a function")
}
if len(args) < 2 {
return ell.Errorf("second argument must be a function")
}
body, handler = &args[0], &args[1]
if result, ok = EvalAny(ell, body, nil); ok {
return
}
msg := NewString(ell.Error)
ell.Error = ""
return EvalAny(ell, handler, msg)
}
func fnThrow(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
return ell.Errorf("%s", args[0].String)
}
func fnPlus(ell *Ell, args []V) (result []V, ok bool) {
res := 0.
for _, arg := range args {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
var value float64
if n, _ := fmt.Sscan(arg.String, &value); n < 1 {
return ell.Errorf("invalid number: %s", arg.String)
}
res += value
}
return []V{*NewNumber(res)}, true
}
func fnMinus(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
var res float64
if n, _ := fmt.Sscan(args[0].String, &res); n < 1 {
return ell.Errorf("invalid number: %f", args[0].String)
}
if len(args) == 1 {
res = -res
}
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
var value float64
if n, _ := fmt.Sscan(arg.String, &value); n < 1 {
return ell.Errorf("invalid number: %f", arg.String)
}
res -= value
}
return []V{*NewNumber(res)}, true
}
func fnMultiply(ell *Ell, args []V) (result []V, ok bool) {
res := 1.
for _, arg := range args {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
var value float64
if n, _ := fmt.Sscan(arg.String, &value); n < 1 {
return ell.Errorf("invalid number: %s", arg.String)
}
res *= value
}
return []V{*NewNumber(res)}, true
}
func fnDivide(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
var res float64
if n, _ := fmt.Sscan(args[0].String, &res); n < 1 {
return ell.Errorf("invalid number: %f", args[0].String)
}
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
var value float64
if n, _ := fmt.Sscan(arg.String, &value); n < 1 {
return ell.Errorf("invalid number: %f", arg.String)
}
res /= value
}
return []V{*NewNumber(res)}, true
}
func fnNot(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 {
return ell.Errorf("missing argument")
}
return []V{*NewBoolean(!Truthy(&args[0]))}, true
}
func fnAnd(ell *Ell, args []V) (result []V, ok bool) {
if args == nil {
return []V{*NewBoolean(true)}, true
}
for _, arg := range args {
result, ok = EvalAny(ell, &arg, nil)
if !ok {
return nil, false
}
if len(result) < 1 || !Truthy(&result[0]) {
return []V{*NewBoolean(false)}, true
}
}
return result, true
}
func fnOr(ell *Ell, args []V) (result []V, ok bool) {
for _, arg := range args {
result, ok = EvalAny(ell, &arg, nil)
if !ok {
return nil, false
}
if len(result) > 0 && Truthy(&result[0]) {
return result, true
}
}
return []V{*NewBoolean(false)}, true
}
func fnEq(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
etalon, res := args[0].String, true
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
if res = etalon == arg.String; !res {
break
}
}
return []V{*NewBoolean(res)}, true
}
func fnLt(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
etalon, res := args[0].String, true
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
if res = etalon < arg.String; !res {
break
}
etalon = arg.String
}
return []V{*NewBoolean(res)}, true
}
func fnEquals(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
var first, second float64
if n, _ := fmt.Sscan(args[0].String, &first); n < 1 {
return ell.Errorf("invalid number: %f", args[0].String)
}
res := true
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
if n, _ := fmt.Sscan(arg.String, &second); n < 1 {
return ell.Errorf("invalid number: %f", arg.String)
}
if res = first == second; !res {
break
}
first = second
}
return []V{*NewBoolean(res)}, true
}
func fnLess(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
var first, second float64
if n, _ := fmt.Sscan(args[0].String, &first); n < 1 {
return ell.Errorf("invalid number: %f", args[0].String)
}
res := true
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
if n, _ := fmt.Sscan(arg.String, &second); n < 1 {
return ell.Errorf("invalid number: %f", arg.String)
}
if res = first < second; !res {
break
}
first = second
}
return []V{*NewBoolean(res)}, true
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
var stdNative = map[string]Handler{
"local": fnLocal,
"set": fnSet,
"list": fnList,
"values": fnValues,
"if": fnIf,
"map": fnMap,
"print": fnPrint,
"..": fnCat,
"system": fnSystem,
"parse": fnParse,
"try": fnTry,
"throw": fnThrow,
"+": fnPlus,
"-": fnMinus,
"*": fnMultiply,
"/": fnDivide,
"not": fnNot,
"and": fnAnd,
"or": fnOr,
"eq?": fnEq,
"lt?": fnLt,
"=": fnEquals,
"<": fnLess,
}
var stdComposed = `
set unless { if (not (@1)) @2 }
set filter { local [_body _list] @1 @2;
map { if (@_body @1) { @1 } } @_list }
set for { local [_list _body] @1 @2;
try { map { @_body @1 } @_list } { if (ne? @1 _break) { throw @1 } } }
set break { throw _break }
# TODO: we should be able to apply them to all arguments
set ne? { not (eq? @1 @2) }; set le? { ge? @2 @1 }
set ge? { not (lt? @1 @2) }; set gt? { lt? @2 @1 }
set <> { not (= @1 @2) }; set <= { >= @2 @1 }
set >= { not (< @1 @2) }; set > { < @2 @1 }`
// StdInitialize initializes the ell standard library.
func StdInitialize(ell *Ell) bool {
for name, handler := range stdNative {
ell.Native[name] = handler
}
p := NewParser([]byte(stdComposed))
program, err := p.Run()
if err != nil {
return false
}
_, ok := ell.EvalBlock(program, nil)
return ok
}

513
ell/stdlib.go Normal file
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@ -0,0 +1,513 @@
//
// Copyright (c) 2018, Přemysl Janouch <p@janouch.name>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
package ell
import (
"bytes"
"fmt"
"os"
"os/exec"
)
// --- Standard library --------------------------------------------------------
// EvalAny evaluates any value and appends to the result.
func EvalAny(ell *Ell, body *V, arg *V) (result []V, ok bool) {
if body.Type == VTypeString {
return []V{*body}, true
}
var args []V
if arg != nil {
args = append(args, *arg.Clone())
}
if res, ok := ell.EvalBlock(body.List, args); ok {
return res, true
}
return nil, false
}
// NewNumber creates a new string value containing a number.
func NewNumber(n float64) *V {
s := fmt.Sprintf("%f", n)
i := len(s)
for i > 0 && s[i-1] == '0' {
i--
}
if s[i-1] == '.' {
i--
}
return NewString(s[:i])
}
// Truthy decides whether any value is logically true.
func Truthy(v *V) bool {
return v != nil && (len(v.List) > 0 || len(v.String) > 0)
}
// NewBoolean creates a new string value copying the boolean's truthiness.
func NewBoolean(b bool) *V {
if b {
return NewString("1")
}
return NewString("")
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
func fnLocal(ell *Ell, args []V) (result []V, ok bool) {
if len(args) == 0 || args[0].Type != VTypeList {
return ell.Errorf("first argument must be a list")
}
// Duplicates or non-strings don't really matter to us, user's problem.
scope := ell.scopes[len(ell.scopes)-1]
values := args[1:]
for _, name := range args[0].List {
if len(values) > 0 {
scope[name.String] = *values[0].Clone()
values = values[1:]
}
}
return nil, true
}
func fnSet(ell *Ell, args []V) (result []V, ok bool) {
if len(args) == 0 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
if len(args) > 1 {
result = []V{*args[1].Clone()}
ell.Set(args[0].String, &result[0])
return result, true
}
// We return an empty list for a nil value.
if v := ell.Get(args[0].String); v != nil {
result = []V{*v.Clone()}
} else {
result = []V{*NewList(nil)}
}
return result, true
}
func fnList(ell *Ell, args []V) (result []V, ok bool) {
return []V{*NewList(args)}, true
}
func fnValues(ell *Ell, args []V) (result []V, ok bool) {
return args, true
}
func fnIf(ell *Ell, args []V) (result []V, ok bool) {
var cond, body, keyword int
for cond = 0; ; cond = keyword + 1 {
if cond >= len(args) {
return ell.Errorf("missing condition")
}
if body = cond + 1; body >= len(args) {
return ell.Errorf("missing body")
}
var res []V
if res, ok = EvalAny(ell, &args[cond], nil); !ok {
return nil, false
}
if len(res) > 0 && Truthy(&res[0]) {
return EvalAny(ell, &args[body], nil)
}
if keyword = body + 1; keyword >= len(args) {
break
}
if args[keyword].Type != VTypeString {
return ell.Errorf("expected keyword, got list")
}
switch kw := args[keyword].String; kw {
case "else":
if body = keyword + 1; body >= len(args) {
return ell.Errorf("missing body")
}
return EvalAny(ell, &args[body], nil)
case "elif":
default:
return ell.Errorf("invalid keyword: %s", kw)
}
}
return nil, true
}
func fnMap(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 {
return ell.Errorf("first argument must be a function")
}
if len(args) < 2 || args[0].Type != VTypeList {
return ell.Errorf("second argument must be a list")
}
body, values := &args[0], &args[1]
for _, v := range values.List {
res, ok := EvalAny(ell, body, &v)
if !ok {
return nil, false
}
result = append(result, res...)
}
return []V{*NewList(result)}, true
}
func fnPrint(ell *Ell, args []V) (result []V, ok bool) {
for _, arg := range args {
if arg.Type != VTypeString {
PrintV(os.Stdout, &arg)
} else if _, err := os.Stdout.WriteString(arg.String); err != nil {
return ell.Errorf("write failed: %s", err)
}
}
return nil, true
}
func fnCat(ell *Ell, args []V) (result []V, ok bool) {
buf := bytes.NewBuffer(nil)
for _, arg := range args {
if arg.Type != VTypeString {
PrintV(buf, &arg)
} else {
buf.WriteString(arg.String)
}
}
return []V{*NewString(buf.String())}, true
}
func fnSystem(ell *Ell, args []V) (result []V, ok bool) {
var argv []string
for _, arg := range args {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
argv = append(argv, arg.String)
}
if len(argv) == 0 {
return ell.Errorf("command name required")
}
cmd := exec.Command(argv[0], argv[1:]...)
cmd.Stdin = os.Stdin
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
// Approximation of system(3) return value to match C ell at least a bit.
if err := cmd.Run(); err == nil {
return []V{*NewNumber(0)}, true
} else if _, ok := err.(*exec.Error); ok {
return ell.Errorf("%s", err)
} else {
return []V{*NewNumber(1)}, true
}
}
func fnParse(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
res, err := NewParser([]byte(args[0].String)).Run()
if err != nil {
return ell.Errorf("%s", err)
}
return []V{*NewList(res)}, true
}
func fnTry(ell *Ell, args []V) (result []V, ok bool) {
var body, handler *V
if len(args) < 1 {
return ell.Errorf("first argument must be a function")
}
if len(args) < 2 {
return ell.Errorf("second argument must be a function")
}
body, handler = &args[0], &args[1]
if result, ok = EvalAny(ell, body, nil); ok {
return
}
msg := NewString(ell.Error)
ell.Error = ""
return EvalAny(ell, handler, msg)
}
func fnThrow(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
return ell.Errorf("%s", args[0].String)
}
func fnPlus(ell *Ell, args []V) (result []V, ok bool) {
res := 0.
for _, arg := range args {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
var value float64
if n, _ := fmt.Sscan(arg.String, &value); n < 1 {
return ell.Errorf("invalid number: %s", arg.String)
}
res += value
}
return []V{*NewNumber(res)}, true
}
func fnMinus(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
var res float64
if n, _ := fmt.Sscan(args[0].String, &res); n < 1 {
return ell.Errorf("invalid number: %f", args[0].String)
}
if len(args) == 1 {
res = -res
}
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
var value float64
if n, _ := fmt.Sscan(arg.String, &value); n < 1 {
return ell.Errorf("invalid number: %f", arg.String)
}
res -= value
}
return []V{*NewNumber(res)}, true
}
func fnMultiply(ell *Ell, args []V) (result []V, ok bool) {
res := 1.
for _, arg := range args {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
var value float64
if n, _ := fmt.Sscan(arg.String, &value); n < 1 {
return ell.Errorf("invalid number: %s", arg.String)
}
res *= value
}
return []V{*NewNumber(res)}, true
}
func fnDivide(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
var res float64
if n, _ := fmt.Sscan(args[0].String, &res); n < 1 {
return ell.Errorf("invalid number: %f", args[0].String)
}
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
var value float64
if n, _ := fmt.Sscan(arg.String, &value); n < 1 {
return ell.Errorf("invalid number: %f", arg.String)
}
res /= value
}
return []V{*NewNumber(res)}, true
}
func fnNot(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 {
return ell.Errorf("missing argument")
}
return []V{*NewBoolean(!Truthy(&args[0]))}, true
}
func fnAnd(ell *Ell, args []V) (result []V, ok bool) {
if args == nil {
return []V{*NewBoolean(true)}, true
}
for _, arg := range args {
result, ok = EvalAny(ell, &arg, nil)
if !ok {
return nil, false
}
if len(result) < 1 || !Truthy(&result[0]) {
return []V{*NewBoolean(false)}, true
}
}
return result, true
}
func fnOr(ell *Ell, args []V) (result []V, ok bool) {
for _, arg := range args {
result, ok = EvalAny(ell, &arg, nil)
if !ok {
return nil, false
}
if len(result) > 0 && Truthy(&result[0]) {
return result, true
}
}
return []V{*NewBoolean(false)}, true
}
func fnEq(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
etalon, res := args[0].String, true
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
if res = etalon == arg.String; !res {
break
}
}
return []V{*NewBoolean(res)}, true
}
func fnLt(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
etalon, res := args[0].String, true
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
if res = etalon < arg.String; !res {
break
}
etalon = arg.String
}
return []V{*NewBoolean(res)}, true
}
func fnEquals(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
var first, second float64
if n, _ := fmt.Sscan(args[0].String, &first); n < 1 {
return ell.Errorf("invalid number: %f", args[0].String)
}
res := true
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
if n, _ := fmt.Sscan(arg.String, &second); n < 1 {
return ell.Errorf("invalid number: %f", arg.String)
}
if res = first == second; !res {
break
}
first = second
}
return []V{*NewBoolean(res)}, true
}
func fnLess(ell *Ell, args []V) (result []V, ok bool) {
if len(args) < 1 || args[0].Type != VTypeString {
return ell.Errorf("first argument must be string")
}
var first, second float64
if n, _ := fmt.Sscan(args[0].String, &first); n < 1 {
return ell.Errorf("invalid number: %f", args[0].String)
}
res := true
for _, arg := range args[1:] {
if arg.Type != VTypeString {
return ell.Errorf("arguments must be strings")
}
if n, _ := fmt.Sscan(arg.String, &second); n < 1 {
return ell.Errorf("invalid number: %f", arg.String)
}
if res = first < second; !res {
break
}
first = second
}
return []V{*NewBoolean(res)}, true
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
var stdNative = map[string]Handler{
"local": fnLocal,
"set": fnSet,
"list": fnList,
"values": fnValues,
"if": fnIf,
"map": fnMap,
"print": fnPrint,
"..": fnCat,
"system": fnSystem,
"parse": fnParse,
"try": fnTry,
"throw": fnThrow,
"+": fnPlus,
"-": fnMinus,
"*": fnMultiply,
"/": fnDivide,
"not": fnNot,
"and": fnAnd,
"or": fnOr,
"eq?": fnEq,
"lt?": fnLt,
"=": fnEquals,
"<": fnLess,
}
var stdComposed = `
set unless { if (not (@1)) @2 }
set filter { local [_body _list] @1 @2;
map { if (@_body @1) { @1 } } @_list }
set for { local [_list _body] @1 @2;
try { map { @_body @1 } @_list } { if (ne? @1 _break) { throw @1 } } }
set break { throw _break }
# TODO: we should be able to apply them to all arguments
set ne? { not (eq? @1 @2) }; set le? { ge? @2 @1 }
set ge? { not (lt? @1 @2) }; set gt? { lt? @2 @1 }
set <> { not (= @1 @2) }; set <= { >= @2 @1 }
set >= { not (< @1 @2) }; set > { < @2 @1 }`
// StdInitialize initializes the ell standard library.
func StdInitialize(ell *Ell) bool {
for name, handler := range stdNative {
ell.Native[name] = handler
}
p := NewParser([]byte(stdComposed))
program, err := p.Run()
if err != nil {
return false
}
_, ok := ell.EvalBlock(program, nil)
return ok
}