Add SLR parsing table generator

1 files changed, 52 insertions, 0 deletions

diff --git a/grammar/test_helper_test.go b/grammar/test_helper_test.go
new file mode 100644
index 0000000..8f5c372
--- /dev/null
+++ b/grammar/test_helper_test.go
@@ -0,0 +1,52 @@
+package grammar
+
+import "testing"
+
+type testSymbolGenerator func(text string) symbol
+
+func newTestSymbolGenerator(t *testing.T, symTab *symbolTable) testSymbolGenerator {
+	return func(text string) symbol {
+		t.Helper()
+
+		sym, ok := symTab.toSymbol(text)
+		if !ok {
+			t.Fatalf("symbol was not found: %v", text)
+		}
+		return sym
+	}
+}
+
+type testProductionGenerator func(lhs string, rhs ...string) *production
+
+func newTestProductionGenerator(t *testing.T, genSym testSymbolGenerator) testProductionGenerator {
+	return func(lhs string, rhs ...string) *production {
+		t.Helper()
+
+		rhsSym := []symbol{}
+		for _, text := range rhs {
+			rhsSym = append(rhsSym, genSym(text))
+		}
+		prod, err := newProduction(genSym(lhs), rhsSym)
+		if err != nil {
+			t.Fatalf("failed to create a production: %v", err)
+		}
+
+		return prod
+	}
+}
+
+type testLR0ItemGenerator func(lhs string, dot int, rhs ...string) *lr0Item
+
+func newTestLR0ItemGenerator(t *testing.T, genProd testProductionGenerator) testLR0ItemGenerator {
+	return func(lhs string, dot int, rhs ...string) *lr0Item {
+		t.Helper()
+
+		prod := genProd(lhs, rhs...)
+		item, err := newLR0Item(prod, dot)
+		if err != nil {
+			t.Fatalf("failed to create a LR0 item: %v", err)
+		}
+
+		return item
+	}
+}