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package parser
//go:generate antlr -Dlanguage=Go -listener -visitor -o gen -package gen Expr.g4
import (
"fmt"
"regexp"
"strconv"
"strings"
"github.com/antlr/antlr4/runtime/Go/antlr"
"github.com/antonmedv/expr/ast"
"github.com/antonmedv/expr/internal/file"
"github.com/antonmedv/expr/parser/gen"
)
type Tree struct {
Node ast.Node
Source *file.Source
}
func Parse(input string) (*Tree, error) {
source := file.NewSource(input)
is := antlr.NewInputStream(input)
lexer := gen.NewExprLexer(is)
stream := antlr.NewCommonTokenStream(lexer, antlr.TokenDefaultChannel)
expr := gen.NewExprParser(stream)
p := &parser{
errors: file.NewErrors(source),
}
lexer.RemoveErrorListeners()
expr.RemoveErrorListeners()
lexer.AddErrorListener(p)
expr.AddErrorListener(p)
antlr.ParseTreeWalkerDefault.Walk(p, expr.Start())
if p.errors.HasError() {
return nil, fmt.Errorf("%v", p.errors.First())
}
if len(p.stack) == 0 {
return nil, fmt.Errorf("empty stack")
}
if len(p.stack) > 1 {
return nil, fmt.Errorf("too long stack")
}
return &Tree{
Node: p.stack[0],
Source: source,
}, nil
}
type parser struct {
*gen.BaseExprListener
stack []ast.Node
errors *file.Errors
closure bool
}
func (p *parser) push(node ast.Node) ast.Node {
p.stack = append(p.stack, node)
return node
}
func (p *parser) pop(ctx antlr.ParserRuleContext, it ...string) ast.Node {
if len(p.stack) == 0 {
if len(it) == 0 {
p.reportError(ctx, "parse error: the expression lacks something")
} else {
p.reportError(ctx, "parse error: the expression lacks "+strings.Join(it, ", "))
}
return &ast.NilNode{}
}
node := p.stack[len(p.stack)-1]
p.stack = p.stack[:len(p.stack)-1]
return node
}
func (p *parser) reportError(ctx antlr.ParserRuleContext, format string, args ...interface{}) {
p.errors.ReportError(location(ctx), format, args...)
}
func (p *parser) EnterIdentifier(ctx *gen.IdentifierContext) {
p.push(&ast.IdentifierNode{Value: ctx.GetText()}).SetLocation(location(ctx))
}
func (p *parser) EnterPointer(ctx *gen.PointerContext) {
p.push(&ast.PointerNode{}).SetLocation(location(ctx))
}
func (p *parser) EnterString(ctx *gen.StringContext) {
var value string
if s, err := unescape(ctx.GetText()); err == nil {
value = s
} else {
p.reportError(ctx, "parse error: %v", err)
return
}
node := &ast.StringNode{
Value: value,
}
p.push(node).SetLocation(location(ctx))
}
func (p *parser) EnterInteger(ctx *gen.IntegerContext) {
if node := ctx.IntegerLiteral(); node != nil {
text := node.GetText()
text = strings.Replace(text, "_", "", -1)
i, err := strconv.ParseInt(text, 10, 64)
if err != nil {
p.reportError(ctx, "parse error: invalid int literal")
return
}
p.push(&ast.IntegerNode{Value: int(i)}).SetLocation(location(ctx))
} else if node := ctx.HexIntegerLiteral(); node != nil {
text := node.GetText()
i, err := strconv.ParseInt(text, 0, 64)
if err != nil {
p.reportError(ctx, "parse error: invalid hex literal")
return
}
p.push(&ast.IntegerNode{Value: int(i)}).SetLocation(location(ctx))
} else {
p.reportError(ctx, "parse error: invalid octal literal")
}
}
func (p *parser) EnterFloat(ctx *gen.FloatContext) {
f, err := strconv.ParseFloat(ctx.GetText(), 64)
if err != nil {
p.reportError(ctx, "parse error: invalid float literal")
return
}
p.push(&ast.FloatNode{Value: f}).SetLocation(location(ctx))
}
func (p *parser) EnterBoolean(ctx *gen.BooleanContext) {
b, err := strconv.ParseBool(ctx.GetText())
if err != nil {
p.reportError(ctx, "parse error: invalid boolean literal")
return
}
p.push(&ast.BoolNode{Value: b}).SetLocation(location(ctx))
}
func (p *parser) EnterNil(ctx *gen.NilContext) {
p.push(&ast.NilNode{}).SetLocation(location(ctx))
}
func (p *parser) ExitUnary(ctx *gen.UnaryContext) {
p.push(&ast.UnaryNode{
Operator: ctx.GetOp().GetText(),
Node: p.pop(ctx),
}).SetLocation(location(ctx))
}
func (p *parser) ExitBinary(ctx *gen.BinaryContext) {
p.push(&ast.BinaryNode{
Operator: ctx.GetOp().GetText(),
Right: p.pop(ctx),
Left: p.pop(ctx),
}).SetLocation(locationToken(ctx.GetOp()))
}
func (p *parser) ExitMatches(ctx *gen.MatchesContext) {
right := p.pop(ctx)
left := p.pop(ctx)
node := &ast.MatchesNode{
Right: right,
Left: left,
}
var err error
var r *regexp.Regexp
if s, ok := right.(*ast.StringNode); ok {
r, err = regexp.Compile(s.Value)
if err != nil {
p.reportError(ctx.GetPattern(), "%v", err)
return
}
node.Regexp = r
}
p.push(node).SetLocation(location(ctx))
}
func (p *parser) ExitCall(ctx *gen.CallContext) {
expr := ctx.GetChild(0)
args := ctx.GetArgs()
var list []gen.IExprContext
if args != nil {
list = args.GetList()
}
arguments := p.arguments(ctx, list)
switch c := expr.(type) {
case *gen.IdentifierContext:
p.push(&ast.FunctionNode{
Arguments: arguments,
Name: p.pop(ctx).(*ast.IdentifierNode).Value,
}).SetLocation(location(ctx))
case *gen.MemberDotContext:
p.push(&ast.MethodNode{
Arguments: arguments,
Method: c.GetName().GetText(),
Node: p.pop(ctx).(*ast.PropertyNode).Node,
}).SetLocation(location(ctx))
default:
p.reportError(ctx, "parse error: undefined call expression")
}
}
func (p *parser) arguments(ctx antlr.ParserRuleContext, list []gen.IExprContext) []ast.Node {
args := make([]ast.Node, 0)
for range list {
args = append([]ast.Node{p.pop(ctx)}, args...)
}
return args
}
func (p *parser) ExitMemberIndex(ctx *gen.MemberIndexContext) {
p.push(&ast.IndexNode{
Index: p.pop(ctx),
Node: p.pop(ctx),
}).SetLocation(location(ctx))
}
func (p *parser) ExitSlice(ctx *gen.SliceContext) {
var a, b ast.Node
if ctx.GetB() != nil {
b = p.pop(ctx)
}
if ctx.GetA() != nil {
a = p.pop(ctx)
}
node := p.pop(ctx)
p.push(&ast.SliceNode{
Node: node,
From: a,
To: b,
}).SetLocation(location(ctx))
}
func (p *parser) ExitMemberDot(ctx *gen.MemberDotContext) {
var property string
name := ctx.GetName()
if name != nil {
property = name.GetText()
}
p.push(&ast.PropertyNode{
Node: p.pop(ctx),
Property: property,
}).SetLocation(location(ctx))
}
func (p *parser) ExitTernary(ctx *gen.TernaryContext) {
expr2 := p.pop(ctx)
expr1 := p.pop(ctx)
cond := p.pop(ctx)
p.push(&ast.ConditionalNode{
Exp2: expr2,
Exp1: expr1,
Cond: cond,
}).SetLocation(location(ctx))
}
func (p *parser) ExitArrayLiteral(ctx *gen.ArrayLiteralContext) {
list := ctx.GetList()
nodes := make([]ast.Node, 0)
for range list {
nodes = append([]ast.Node{p.pop(ctx)}, nodes...)
}
p.push(&ast.ArrayNode{Nodes: nodes}).SetLocation(location(ctx))
}
func (p *parser) ExitMapLiteral(ctx *gen.MapLiteralContext) {
e := ctx.GetE()
if e == nil {
p.push(&ast.MapNode{}).SetLocation(location(ctx))
return
}
nodes := make([]ast.Node, 0)
for range e.GetList() {
nodes = append([]ast.Node{p.pop(ctx).(*ast.PairNode)}, nodes...)
}
p.push(&ast.MapNode{Pairs: nodes}).SetLocation(location(ctx))
}
func (p *parser) ExitPropertyAssignment(ctx *gen.PropertyAssignmentContext) {
value := p.pop(ctx)
name := ctx.GetName().(*gen.PropertyNameContext)
var s string
if id := name.Identifier(); id != nil {
s = id.GetText()
} else if str := name.StringLiteral(); str != nil {
s2, err := unescape(str.GetText())
if err != nil {
p.reportError(ctx, "parse error: %v", err)
return
}
s = s2
} else {
p.reportError(ctx, "parse error: invalid key type")
return
}
key := &ast.StringNode{Value: s}
key.SetLocation(location(ctx))
p.push(&ast.PairNode{
Key: key,
Value: value,
}).SetLocation(location(ctx))
}
func (p *parser) ExitBuiltinLen(ctx *gen.BuiltinLenContext) {
name := ctx.GetName().GetText()
node := p.pop(ctx.GetE())
p.push(&ast.BuiltinNode{
Name: name,
Arguments: []ast.Node{node},
}).SetLocation(location(ctx))
}
func (p *parser) ExitBuiltin(ctx *gen.BuiltinContext) {
name := ctx.GetName().GetText()
closure := p.pop(ctx.GetC())
node := p.pop(ctx.GetE())
p.push(&ast.BuiltinNode{
Name: name,
Arguments: []ast.Node{node, closure},
}).SetLocation(location(ctx))
}
func (p *parser) EnterClosure(ctx *gen.ClosureContext) {
p.closure = true
}
func (p *parser) ExitClosure(ctx *gen.ClosureContext) {
p.closure = false
p.push(&ast.ClosureNode{
Node: p.pop(ctx),
}).SetLocation(location(ctx))
}
func (p *parser) ExitClosureMemberDot(ctx *gen.ClosureMemberDotContext) {
if !p.closure {
p.reportError(ctx, "parse error: dot property accessor can be only inside closure")
return
}
var property string
name := ctx.GetName()
if name != nil {
property = name.GetText()
}
pointer := &ast.PointerNode{}
pointer.SetLocation(location(ctx))
p.push(&ast.PropertyNode{
Node: pointer,
Property: property,
}).SetLocation(location(ctx))
}
func (p *parser) SyntaxError(recognizer antlr.Recognizer, offendingSymbol interface{}, line, column int, msg string, e antlr.RecognitionException) {
p.errors.ReportError(file.Location{Line: line, Column: column}, fmt.Sprintf("syntax error: %s", msg))
}
func (p *parser) ReportAmbiguity(_ antlr.Parser, _ *antlr.DFA, _, _ int, _ bool, _ *antlr.BitSet, _ antlr.ATNConfigSet) {
}
func (p *parser) ReportAttemptingFullContext(_ antlr.Parser, _ *antlr.DFA, _, _ int, _ *antlr.BitSet, _ antlr.ATNConfigSet) {
}
func (p *parser) ReportContextSensitivity(_ antlr.Parser, _ *antlr.DFA, _, _, _ int, _ antlr.ATNConfigSet) {
}
func location(ctx antlr.ParserRuleContext) file.Location {
if ctx == nil {
return file.Location{Line: 0, Column: 0}
}
token := ctx.GetStart()
if token == nil {
return file.Location{Line: 0, Column: 0}
}
return file.Location{Line: token.GetLine(), Column: token.GetColumn()}
}
func locationToken(token antlr.Token) file.Location {
return file.Location{Line: token.GetLine(), Column: token.GetColumn()}
}
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