Import source code of lexer generator

From: https://github.com/nihei9/maleeni

1 files changed, 227 insertions, 0 deletions

diff --git a/driver/parser/semantic_action_test.go b/driver/parser/semantic_action_test.go
new file mode 100644
index 0000000..c98a12f
--- /dev/null
+++ b/driver/parser/semantic_action_test.go
@@ -0,0 +1,227 @@
+package parser
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/nihei9/vartan/grammar"
+	spec "github.com/nihei9/vartan/spec/grammar"
+	"github.com/nihei9/vartan/spec/grammar/parser"
+)
+
+type testSemAct struct {
+	gram   *spec.CompiledGrammar
+	actLog []string
+}
+
+func (a *testSemAct) Shift(tok VToken, recovered bool) {
+	t := a.gram.Syntactic.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.Syntactic.LHSSymbols[prodNum]
+	lhsText := a.gram.Syntactic.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 := parser.Parse(strings.NewReader(tt.specSrc))
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			b := grammar.GrammarBuilder{
+				AST: ast,
+			}
+			gram, _, err := b.Build()
+			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)
+				}
+			}
+		})
+	}
+}