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|
package driver
import (
"fmt"
"strings"
"testing"
"github.com/nihei9/vartan/grammar"
"github.com/nihei9/vartan/spec"
)
type testSemAct struct {
gram *spec.CompiledGrammar
actLog []string
}
func (a *testSemAct) Shift(tok VToken, recovered bool) {
t := a.gram.ParsingTable.Terminals[tok.TerminalID()]
if recovered {
a.actLog = append(a.actLog, fmt.Sprintf("shift/%v/recovered", t))
} else {
a.actLog = append(a.actLog, fmt.Sprintf("shift/%v", t))
}
}
func (a *testSemAct) Reduce(prodNum int, recovered bool) {
lhsSym := a.gram.ParsingTable.LHSSymbols[prodNum]
lhsText := a.gram.ParsingTable.NonTerminals[lhsSym]
if recovered {
a.actLog = append(a.actLog, fmt.Sprintf("reduce/%v/recovered", lhsText))
} else {
a.actLog = append(a.actLog, fmt.Sprintf("reduce/%v", lhsText))
}
}
func (a *testSemAct) Accept() {
a.actLog = append(a.actLog, "accept")
}
func (a *testSemAct) TrapAndShiftError(cause VToken, popped int) {
a.actLog = append(a.actLog, fmt.Sprintf("trap/%v/shift/error", popped))
}
func (a *testSemAct) MissError(cause VToken) {
a.actLog = append(a.actLog, "miss")
}
func TestParserWithSemanticAction(t *testing.T) {
specSrcWithErrorProd := `
#name test;
seq
: seq elem semicolon
| elem semicolon
| error star star semicolon
| error semicolon #recover
;
elem
: char char char
;
ws #skip
: "[\u{0009}\u{0020}]+";
semicolon
: ';';
star
: '*';
char
: "[a-z]";
`
specSrcWithoutErrorProd := `
#name test;
seq
: seq elem semicolon
| elem semicolon
;
elem
: char char char
;
ws #skip
: "[\u{0009}\u{0020}]+";
semicolon
: ';';
char
: "[a-z]";
`
tests := []struct {
caption string
specSrc string
src string
actLog []string
}{
{
caption: "when an input contains no syntax error, the driver calls `Shift`, `Reduce`, and `Accept`.",
specSrc: specSrcWithErrorProd,
src: `a b c; d e f;`,
actLog: []string{
"shift/char",
"shift/char",
"shift/char",
"reduce/elem",
"shift/semicolon",
"reduce/seq",
"shift/char",
"shift/char",
"shift/char",
"reduce/elem",
"shift/semicolon",
"reduce/seq",
"accept",
},
},
{
caption: "when a grammar has `error` symbol, the driver calls `TrapAndShiftError`.",
specSrc: specSrcWithErrorProd,
src: `a; b !; c d !; e ! * *; h i j;`,
actLog: []string{
"shift/char",
"trap/1/shift/error",
"shift/semicolon",
"reduce/seq/recovered",
"shift/char",
"trap/2/shift/error",
"shift/semicolon",
"reduce/seq/recovered",
"shift/char",
"shift/char",
"trap/3/shift/error",
"shift/semicolon",
"reduce/seq/recovered",
"shift/char",
"trap/2/shift/error",
"shift/star",
"shift/star",
// When the driver shifts three times, it recovers from an error.
"shift/semicolon/recovered",
"reduce/seq",
"shift/char",
"shift/char",
"shift/char",
"reduce/elem",
"shift/semicolon",
"reduce/seq",
// Even if the input contains syntax errors, the driver calls `Accept` when the input is accepted
// according to the error production.
"accept",
},
},
{
caption: "when the input doesn't meet the error production, the driver calls `MissError`.",
specSrc: specSrcWithErrorProd,
src: `a !`,
actLog: []string{
"shift/char",
"trap/1/shift/error",
"miss",
},
},
{
caption: "when a syntax error isn't trapped, the driver calls `MissError`.",
specSrc: specSrcWithoutErrorProd,
src: `a !`,
actLog: []string{
"shift/char",
"miss",
},
},
}
for _, tt := range tests {
t.Run(tt.caption, func(t *testing.T) {
ast, err := spec.Parse(strings.NewReader(tt.specSrc))
if err != nil {
t.Fatal(err)
}
b := grammar.GrammarBuilder{
AST: ast,
}
g, err := b.Build()
if err != nil {
t.Fatal(err)
}
gram, _, err := grammar.Compile(g)
if err != nil {
t.Fatal(err)
}
toks, err := NewTokenStream(gram, strings.NewReader(tt.src))
if err != nil {
t.Fatal(err)
}
semAct := &testSemAct{
gram: gram,
}
p, err := NewParser(toks, NewGrammar(gram), SemanticAction(semAct))
if err != nil {
t.Fatal(err)
}
err = p.Parse()
if err != nil {
t.Fatal(err)
}
if len(semAct.actLog) != len(tt.actLog) {
t.Fatalf("unexpected action log; want: %+v, got: %+v", tt.actLog, semAct.actLog)
}
for i, e := range tt.actLog {
if semAct.actLog[i] != e {
t.Fatalf("unexpected action log; want: %+v, got: %+v", tt.actLog, semAct.actLog)
}
}
})
}
}
|
