Expr's functions now support parameters with default value

This commit is contained in:
Celestino Amoroso 2024-06-01 19:56:40 +02:00
parent f66cd1fdb1
commit 9bba40f155
12 changed files with 180 additions and 247 deletions

View File

@ -168,11 +168,11 @@ func mulFunc(ctx ExprContext, name string, args []any) (result any, err error) {
func ImportMathFuncs(ctx ExprContext) {
ctx.RegisterFunc("add", &golangFunctor{f: addFunc}, typeNumber, []ExprFuncParam{
newFuncParamFlagDef(paramValue, pfOptional|pfRepeat, 0),
newFuncParamFlagDef(paramValue, pfOptional|pfRepeat, int64(0)),
})
ctx.RegisterFunc("mul", &golangFunctor{f: mulFunc}, typeNumber, []ExprFuncParam{
newFuncParamFlagDef(paramValue, pfOptional|pfRepeat, 1),
newFuncParamFlagDef(paramValue, pfOptional|pfRepeat, int64(1)),
})
}

View File

@ -49,55 +49,8 @@ func (h *osReader) getFile() *os.File {
return h.fh
}
func createFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
var filePath string
if len(args) > 0 {
filePath, _ = args[0].(string)
}
if len(filePath) > 0 {
var fh *os.File
if fh, err = os.Create(filePath); err == nil {
result = &osWriter{fh: fh, writer: bufio.NewWriter(fh)}
}
} else {
err = fmt.Errorf("%s(): missing the file path", name)
}
return
}
func openFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
var filePath string
if len(args) > 0 {
filePath, _ = args[0].(string)
}
if len(filePath) > 0 {
var fh *os.File
if fh, err = os.Open(filePath); err == nil {
result = &osReader{fh: fh, reader: bufio.NewReader(fh)}
}
} else {
err = fmt.Errorf("%s(): missing the file path", name)
}
return
}
func appendFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
var filePath string
if len(args) > 0 {
filePath, _ = args[0].(string)
}
if len(filePath) > 0 {
var fh *os.File
if fh, err = os.OpenFile(filePath, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0660); err == nil {
result = &osWriter{fh: fh, writer: bufio.NewWriter(fh)}
}
} else {
err = fmt.Errorf("%s(): missing the file path", name)
}
return
func errMissingFilePath(funcName string) error {
return fmt.Errorf("%s(): missing or invalid file path", funcName)
}
func errInvalidFileHandle(funcName string, v any) error {
@ -108,16 +61,50 @@ func errInvalidFileHandle(funcName string, v any) error {
}
}
func createFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
if filePath, ok := args[0].(string); ok && len(filePath) > 0 {
var fh *os.File
if fh, err = os.Create(filePath); err == nil {
result = &osWriter{fh: fh, writer: bufio.NewWriter(fh)}
}
} else {
err = errMissingFilePath("createFile")
}
return
}
func openFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
if filePath, ok := args[0].(string); ok && len(filePath) > 0 {
var fh *os.File
if fh, err = os.Open(filePath); err == nil {
result = &osReader{fh: fh, reader: bufio.NewReader(fh)}
}
} else {
err = errMissingFilePath("openFile")
}
return
}
func appendFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
if filePath, ok := args[0].(string); ok && len(filePath) > 0 {
var fh *os.File
if fh, err = os.OpenFile(filePath, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0660); err == nil {
result = &osWriter{fh: fh, writer: bufio.NewWriter(fh)}
}
} else {
err = errMissingFilePath("openFile")
}
return
}
func closeFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
var handle osHandle
var invalidFileHandle any
if len(args) > 0 {
var ok bool
if handle, ok = args[0].(osHandle); !ok {
invalidFileHandle = args[0]
}
}
if handle != nil {
if fh := handle.getFile(); fh != nil {
@ -140,13 +127,11 @@ func closeFileFunc(ctx ExprContext, name string, args []any) (result any, err er
func writeFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
var handle osHandle
var invalidFileHandle any
if len(args) > 0 {
var ok bool
if handle, ok = args[0].(osHandle); !ok {
invalidFileHandle = args[0]
}
}
if handle != nil {
if w, ok := handle.(*osWriter); ok {
@ -165,24 +150,21 @@ func writeFileFunc(ctx ExprContext, name string, args []any) (result any, err er
func readFileFunc(ctx ExprContext, name string, args []any) (result any, err error) {
var handle osHandle
var invalidFileHandle any
var ok bool
result = nil
if len(args) > 0 {
var ok bool
if handle, ok = args[0].(osHandle); !ok || args[0] == nil {
invalidFileHandle = args[0]
}
}
if handle != nil {
if r, ok := handle.(*osReader); ok {
var limit byte = '\n'
var v string
if len(args) > 1 {
if s, ok := args[1].(string); ok && len(s) > 0 {
limit = s[0]
}
}
if v, err = r.reader.ReadString(limit); err == nil {
if len(v) > 0 && v[len(v)-1] == limit {
result = v[0 : len(v)-1]
@ -220,7 +202,7 @@ func ImportOsFuncs(ctx ExprContext) {
})
ctx.RegisterFunc("readFile", newGolangFunctor(readFileFunc), typeString, []ExprFuncParam{
newFuncParam(typeHandle),
newFuncParamFlagDef("limitCh", pfOptional, "\\n"),
newFuncParamFlagDef("limitCh", pfOptional, "\n"),
})
ctx.RegisterFunc("closeFile", newGolangFunctor(closeFileFunc), typeBoolean, []ExprFuncParam{
newFuncParam(typeHandle),

View File

@ -65,19 +65,19 @@ func subStrFunc(ctx ExprContext, name string, args []any) (result any, err error
if source, ok = args[0].(string); !ok {
return nil, errWrongParamType(name, paramSource, typeString, args[0])
}
if len(args) > 1 {
if start, err = toInt(args[1], name+"()"); err != nil {
return
}
if len(args) > 2 {
if count, err = toInt(args[2], name+"()"); err != nil {
return
}
}
if start < 0 {
start = len(source) + start
}
}
if count < 0 {
count = len(source) - start
}
@ -152,18 +152,17 @@ func splitStrFunc(ctx ExprContext, name string, args []any) (result any, err err
if source, ok = args[0].(string); !ok {
return result, errWrongParamType(name, paramSource, typeString, args[0])
}
if len(args) >= 2 {
if sep, ok = args[1].(string); !ok {
return nil, fmt.Errorf("separator param must be string, got %T (%v)", args[1], args[1])
}
if len(args) >= 3 {
if count64, ok := args[2].(int64); ok { // TODO replace type assertion with toInt()
count = int(count64)
} else {
return nil, fmt.Errorf("part count must be integer, got %T (%v)", args[2], args[2])
}
}
}
if count > 0 {
parts = strings.SplitN(source, sep, count)
} else if count < 0 {
@ -190,14 +189,14 @@ func ImportStringFuncs(ctx ExprContext) {
ctx.RegisterFunc("subStr", newGolangFunctor(subStrFunc), typeString, []ExprFuncParam{
newFuncParam(paramSource),
newFuncParamFlagDef(paramStart, pfOptional, 0),
newFuncParamFlagDef(paramCount, pfOptional, -1),
newFuncParamFlagDef(paramStart, pfOptional, int64(0)),
newFuncParamFlagDef(paramCount, pfOptional, int64(-1)),
})
ctx.RegisterFunc("splitStr", newGolangFunctor(splitStrFunc), "list of "+typeString, []ExprFuncParam{
newFuncParam(paramSource),
newFuncParamFlagDef(paramSeparator, pfOptional, ""),
newFuncParamFlagDef(paramCount, pfOptional, -1),
newFuncParamFlagDef(paramCount, pfOptional, int64(-1)),
})
ctx.RegisterFunc("trimStr", newGolangFunctor(trimStrFunc), typeString, []ExprFuncParam{

View File

@ -59,12 +59,16 @@ func (functor *golangFunctor) Invoke(ctx ExprContext, name string, args []any) (
// ---- Linking with Expr functions
type exprFunctor struct {
baseFunctor
params []string
params []ExprFuncParam
expr Expr
defCtx ExprContext
}
func newExprFunctor(e Expr, params []string, ctx ExprContext) *exprFunctor {
// func newExprFunctor(e Expr, params []string, ctx ExprContext) *exprFunctor {
// return &exprFunctor{expr: e, params: params, defCtx: ctx}
// }
func newExprFunctor(e Expr, params []ExprFuncParam, ctx ExprContext) *exprFunctor {
return &exprFunctor{expr: e, params: params, defCtx: ctx}
}
@ -79,12 +83,12 @@ func (functor *exprFunctor) Invoke(ctx ExprContext, name string, args []any) (re
if funcArg, ok := arg.(Functor); ok {
// ctx.RegisterFunc(p, functor, 0, -1)
paramSpecs := funcArg.GetParams()
ctx.RegisterFunc(p, funcArg, typeAny, paramSpecs)
ctx.RegisterFunc(p.Name(), funcArg, typeAny, paramSpecs)
} else {
ctx.UnsafeSetVar(p, arg)
ctx.UnsafeSetVar(p.Name(), arg)
}
} else {
ctx.UnsafeSetVar(p, nil)
ctx.UnsafeSetVar(p.Name(), nil)
}
}
result, err = functor.expr.eval(ctx, false)

View File

@ -22,13 +22,22 @@ func newFuncCallTerm(tk *Token, args []*term) *term {
}
// -------- eval func call
func checkFunctionCall(ctx ExprContext, name string, params []any) (err error) {
func checkFunctionCall(ctx ExprContext, name string, varParams *[]any) (err error) {
if info, exists, owner := GetFuncInfo(ctx, name); exists {
if info.MinArgs() > len(params) {
err = errTooFewParams(name, info.MinArgs(), info.MaxArgs(), len(params))
passedCount := len(*varParams)
if info.MinArgs() > passedCount {
err = errTooFewParams(name, info.MinArgs(), info.MaxArgs(), passedCount)
}
if err == nil && info.MaxArgs() >= 0 && info.MaxArgs() < len(params) {
err = errTooMuchParams(name, info.MaxArgs(), len(params))
for i, p := range info.Params() {
if i >= passedCount {
if !p.IsOptional() {
break
}
*varParams = append(*varParams, p.DefaultValue())
}
}
if err == nil && info.MaxArgs() >= 0 && info.MaxArgs() < len(*varParams) {
err = errTooMuchParams(name, info.MaxArgs(), len(*varParams))
}
if err == nil && owner != ctx {
// ctx.RegisterFunc(name, info.Functor(), info.MinArgs(), info.MaxArgs())
@ -44,7 +53,7 @@ func evalFuncCall(parentCtx ExprContext, self *term) (v any, err error) {
ctx := cloneContext(parentCtx)
name, _ := self.tk.Value.(string)
// fmt.Printf("Call %s(), context: %p\n", name, ctx)
params := make([]any, len(self.children))
params := make([]any, len(self.children), len(self.children)+5)
for i, tree := range self.children {
var param any
if param, err = tree.compute(ctx); err != nil {
@ -52,8 +61,9 @@ func evalFuncCall(parentCtx ExprContext, self *term) (v any, err error) {
}
params[i] = param
}
if err == nil {
if err = checkFunctionCall(ctx, name, params); err == nil {
if err = checkFunctionCall(ctx, name, &params); err == nil {
if v, err = ctx.Call(name, params); err == nil {
exportObjects(parentCtx, ctx)
}
@ -75,12 +85,35 @@ func newFuncDefTerm(tk *Token, args []*term) *term {
}
// -------- eval func def
// func _evalFuncDef(ctx ExprContext, self *term) (v any, err error) {
// bodySpec := self.value()
// if expr, ok := bodySpec.(*ast); ok {
// paramList := make([]string, 0, len(self.children))
// for _, param := range self.children {
// paramList = append(paramList, param.source())
// }
// v = newExprFunctor(expr, paramList, ctx)
// } else {
// err = errors.New("invalid function definition: the body specification must be an expression")
// }
// return
// }
func evalFuncDef(ctx ExprContext, self *term) (v any, err error) {
bodySpec := self.value()
if expr, ok := bodySpec.(*ast); ok {
paramList := make([]string, 0, len(self.children))
paramList := make([]ExprFuncParam, 0, len(self.children))
for _, param := range self.children {
paramList = append(paramList, param.source())
var defValue any
flags := paramFlags(0)
if len(param.children) > 0 {
flags |= pfOptional
if defValue, err = param.children[0].compute(ctx); err != nil {
return
}
}
info := newFuncParamFlagDef(param.source(), flags, defValue)
paramList = append(paramList, info)
}
v = newExprFunctor(expr, paramList, ctx)
} else {

View File

@ -10,8 +10,6 @@ import "fmt"
func newVarTerm(tk *Token) *term {
t := &term{
tk: *tk,
// class: classVar,
// kind: kindUnknown,
parent: nil,
children: nil,
position: posLeaf,

View File

@ -36,12 +36,9 @@ func evalAssign(ctx ExprContext, self *term) (v any, err error) {
// ctx.RegisterFuncInfo(info)
ctx.RegisterFunc(leftTerm.source(), info.Functor(), info.ReturnType(), info.Params())
} else if funcDef, ok := functor.(*exprFunctor); ok {
paramSpecs := ForAll(funcDef.params, newFuncParam)
// paramCount := len(funcDef.params)
// paramSpecs := make([]ExprFuncParam, paramCount)
// for i := range paramSpecs {
// paramSpecs[i] = newFuncParam(funcDef.params[i])
// }
// paramSpecs := ForAll(funcDef.params, newFuncParam)
paramSpecs := ForAll(funcDef.params, func(p ExprFuncParam) ExprFuncParam { return p })
ctx.RegisterFunc(leftTerm.source(), functor, typeAny, paramSpecs)
} else {
err = self.Errorf("unknown function %s()", funcName)

101
parser.go
View File

@ -23,34 +23,28 @@ func NewParser(ctx ExprContext) (p *parser) {
}
func (self *parser) parseFuncCall(scanner *scanner, allowVarRef bool, tk *Token) (tree *term, err error) {
// name, _ := tk.Value.(string)
// funcObj := self.ctx.GetFuncInfo(name)
// if funcObj == nil {
// err = fmt.Errorf("unknown function %s()", name)
// return
// }
// maxArgs := funcObj.MaxArgs()
// if maxArgs < 0 {
// maxArgs = funcObj.MinArgs() + 10
// }
// args := make([]*term, 0, maxArgs)
args := make([]*term, 0, 10)
itemExpected := false
lastSym := SymUnknown
for lastSym != SymClosedRound && lastSym != SymEos {
var subTree *ast
if subTree, err = self.parseItem(scanner, allowVarRef, SymComma, SymClosedRound); err == nil {
if subTree.root != nil {
args = append(args, subTree.root)
}
} else {
if subTree, err = self.parseItem(scanner, allowVarRef, SymComma, SymClosedRound); err != nil {
break
}
prev := scanner.Previous()
if subTree.root != nil {
args = append(args, subTree.root)
} else if itemExpected {
err = prev.ErrorExpectedGot("function-param-value")
break
}
itemExpected = prev.Sym == SymComma
lastSym = scanner.Previous().Sym
}
if err == nil {
// TODO Check arguments
if lastSym != SymClosedRound {
err = errors.New("unterminate arguments list")
err = errors.New("unterminated arguments list")
} else {
tree = newFuncCallTerm(tk, args)
}
@ -58,62 +52,12 @@ func (self *parser) parseFuncCall(scanner *scanner, allowVarRef bool, tk *Token)
return
}
// func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
// // Example: "add = func(x,y) {x+y}
// var body *ast
// args := make([]*term, 0)
// lastSym := SymUnknown
// itemExpected := false
// tk := scanner.Previous()
// for lastSym != SymClosedRound && lastSym != SymEos {
// var subTree *ast
// if subTree, err = self.parseItem(scanner, true, SymComma, SymClosedRound); err == nil {
// if subTree.root != nil {
// if subTree.root.symbol() == SymIdentifier {
// args = append(args, subTree.root)
// } else {
// err = tk.ErrorExpectedGotString("param-name", subTree.root.String())
// }
// } else if itemExpected {
// prev := scanner.Previous()
// err = prev.ErrorExpectedGot("function-param")
// break
// }
// } else {
// break
// }
// lastSym = scanner.Previous().Sym
// itemExpected = lastSym == SymComma
// }
// if err == nil && lastSym != SymClosedRound {
// err = tk.ErrorExpectedGot(")")
// }
// if err == nil {
// tk = scanner.Next()
// if tk.Sym == SymOpenBrace {
// body, err = self.parseGeneral(scanner, true, true, SymClosedBrace)
// } else {
// err = tk.ErrorExpectedGot("{")
// }
// }
// if err == nil {
// // TODO Check arguments
// if scanner.Previous().Sym != SymClosedBrace {
// err = scanner.Previous().ErrorExpectedGot("}")
// } else {
// tk = scanner.makeValueToken(SymExpression, "", body)
// tree = newFuncDefTerm(tk, args)
// }
// }
// return
// }
func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
// Example: "add = func(x,y) {x+y}
var body *ast
args := make([]*term, 0)
lastSym := SymUnknown
defaultParamsStarted := false
itemExpected := false
tk := scanner.Previous()
for lastSym != SymClosedRound && lastSym != SymEos {
@ -122,9 +66,20 @@ func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
param := newTerm(tk)
args = append(args, param)
tk = scanner.Next()
if tk.Sym == SymEqual {
var paramExpr *ast
defaultParamsStarted = true
if paramExpr, err = self.parseItem(scanner, false, SymComma, SymClosedRound); err != nil {
break
}
param.forceChild(paramExpr.root)
} else if defaultParamsStarted {
err = tk.Errorf("can't mix default and non-default parameters")
break
}
} else if itemExpected {
prev := scanner.Previous()
err = prev.ErrorExpectedGot("function-param")
err = prev.ErrorExpectedGot("function-param-spec")
break
}
lastSym = scanner.Previous().Sym
@ -143,7 +98,6 @@ func (self *parser) parseFuncDef(scanner *scanner) (tree *term, err error) {
}
}
if err == nil {
// TODO Check arguments
if scanner.Previous().Sym != SymClosedBrace {
err = scanner.Previous().ErrorExpectedGot("}")
} else {
@ -225,7 +179,6 @@ func (self *parser) parseIterDef(scanner *scanner, allowVarRef bool) (subtree *t
itemExpected = lastSym == SymComma
}
if err == nil {
// TODO Check arguments
if lastSym != SymClosedRound {
err = scanner.Previous().ErrorExpectedGot(")")
} else {
@ -252,7 +205,6 @@ func (self *parser) parseDictKey(scanner *scanner, allowVarRef bool) (key any, e
key = tk.Value
}
} else {
// err = tk.Errorf("expected dictionary key or closed brace, got %q", tk)
err = tk.ErrorExpectedGot("dictionary-key or }")
}
return
@ -290,7 +242,6 @@ func (self *parser) parseDictionary(scanner *scanner, allowVarRef bool) (subtree
itemExpected = lastSym == SymComma
}
if err == nil {
// TODO Check arguments
if lastSym != SymClosedBrace {
err = scanner.Previous().ErrorExpectedGot("}")
} else {
@ -394,6 +345,8 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
if allowForest {
tree.ToForest()
firstToken = true
currentTerm = nil
selectorTerm = nil
continue
} else {
err = tk.Errorf(`unexpected token %q, expected ",", "]", or ")"`, tk.source)

View File

@ -5,21 +5,16 @@
package expr
import (
"strings"
"testing"
)
func TestExpr(t *testing.T) {
type inputType struct {
source string
wantResult any
wantErr error
}
section := "Expr"
inputs := []inputType{
/* 1 */ {`0?{}`, nil, nil},
/* 2 */ {`fact=func(n){(n)?{1}::{n*fact(n-1)}}; fact(5)`, int64(120), nil},
/* 3 */ {`f=openFile("test-file.txt"); line=readFile(f); closeFile(f); line`, "uno", nil},
/* 3 */ {`builtin "os.file"; f=openFile("test-file.txt"); line=readFile(f); closeFile(f); line`, "uno", nil},
/* 4 */ {`mynot=func(v){int(v)?{true}::{false}}; mynot(0)`, true, nil},
/* 5 */ {`1 ? {1} : [1+0] {3*(1+1)}`, int64(6), nil},
/* 6 */ {`
@ -35,48 +30,8 @@ func TestExpr(t *testing.T) {
it++
`, int64(1), nil},
}
// t.Setenv("EXPR_PATH", ".")
succeeded := 0
failed := 0
for i, input := range inputs {
var expr Expr
var gotResult any
var gotErr error
ctx := NewSimpleStore()
// ImportMathFuncs(ctx)
// ImportImportFunc(ctx)
ImportOsFuncs(ctx)
parser := NewParser(ctx)
logTest(t, i+1, "Expr", input.source, input.wantResult, input.wantErr)
r := strings.NewReader(input.source)
scanner := NewScanner(r, DefaultTranslations())
good := true
if expr, gotErr = parser.Parse(scanner); gotErr == nil {
gotResult, gotErr = expr.Eval(ctx)
}
if gotResult != input.wantResult {
t.Errorf("%d: %q -> result = %v [%T], want %v [%T]", i+1, input.source, gotResult, gotResult, input.wantResult, input.wantResult)
good = false
}
if gotErr != input.wantErr {
if input.wantErr == nil || gotErr == nil || (gotErr.Error() != input.wantErr.Error()) {
t.Errorf("%d: %q -> err = <%v>, want <%v>", i+1, input.source, gotErr, input.wantErr)
good = false
}
}
if good {
succeeded++
} else {
failed++
}
}
t.Logf("test count: %d, succeeded count: %d, failed count: %d", len(inputs), succeeded, failed)
// parserTestSpec(t, section, inputs, 3)
parserTest(t, section, inputs)
}

View File

@ -29,7 +29,7 @@ func TestFuncString(t *testing.T) {
/* 14 */ {`builtin "string"; endsWithStr("0123456789", "xyz", "789")`, true, nil},
/* 15 */ {`builtin "string"; endsWithStr("0123456789", "xyz", "0125")`, false, nil},
/* 16 */ {`builtin "string"; endsWithStr("0123456789")`, nil, errors.New(`endsWithStr(): too few params -- expected 2 or more, got 1`)},
/* 17 */ {`builtin "string"; splitStr("one-two-three", "-", )`, newListA("one", "two", "three"), nil},
/* 17 */ {`builtin "string"; splitStr("one-two-three", "-")`, newListA("one", "two", "three"), nil},
/* 18 */ {`builtin "string"; joinStr("-", [1, "two", "three"])`, nil, errors.New(`joinStr() expected string, got int64 (1)`)},
/* 19 */ {`builtin "string"; joinStr()`, nil, errors.New(`joinStr(): too few params -- expected 1 or more, got 0`)},

View File

@ -26,11 +26,14 @@ func TestFuncs(t *testing.T) {
/* 12 */ {`f=func(@y){g=func(){@x=5}; g(); @z=x; @x=@y+@z}; f(2); y+x`, int64(9), nil},
/* 13 */ {`two=func(){2}; four=func(f){f()+f()}; four(two)`, int64(4), nil},
/* 14 */ {`two=func(){2}; two(123)`, nil, errors.New(`two(): too much params -- expected 0, got 1`)},
/* 15 */ {`f=func(x,n=2){x+n}; f(3)`, int64(5), nil},
/* 16 */ {`f=func(x,n=2,y){x+n}`, nil, errors.New(`[1:16] can't mix default and non-default parameters`)},
/* 17 */ {`f=func(x,n){1}; f(3,4,)`, nil, errors.New(`[1:24] expected "function-param-value", got ")"`)},
}
t.Setenv("EXPR_PATH", ".")
// t.Setenv("EXPR_PATH", ".")
// parserTestSpec(t, section, inputs, 69)
// parserTestSpec(t, section, inputs, 17)
parserTest(t, section, inputs)
}

View File

@ -229,3 +229,12 @@ func (self *term) evalPrefix(ctx ExprContext) (childValue any, err error) {
}
return
}
// NOTE Temporary solution to support function parameters with default value
func (self *term) forceChild(c *term) {
if self.children == nil {
self.children = make([]*term, 0, 1)
}
self.children = append(self.children, c)
}