diff options
Diffstat (limited to 'grammar/lr0_test.go')
| -rw-r--r-- | grammar/lr0_test.go | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/grammar/lr0_test.go b/grammar/lr0_test.go new file mode 100644 index 0000000..9000483 --- /dev/null +++ b/grammar/lr0_test.go @@ -0,0 +1,266 @@ +package grammar + +import ( + "fmt" + "strings" + "testing" + + "github.com/nihei9/vartan/spec" +) + +type expectedLR0State struct { + kernelItems []*lrItem + nextStates map[symbol][]*lrItem + reducibleProds []*production +} + +func TestGenLR0Automaton(t *testing.T) { + src := ` +expr + : expr add term + | term + ; +term + : term mul factor + | factor + ; +factor + : l_paren expr r_paren + | id + ; +add: "\+"; +mul: "\*"; +l_paren: "\("; +r_paren: "\)"; +id: "[A-Za-z_][0-9A-Za-z_]*"; +` + + ast, err := spec.Parse(strings.NewReader(src)) + if err != nil { + t.Fatal(err) + } + b := GrammarBuilder{ + AST: ast, + } + gram, err := b.Build() + if err != nil { + t.Fatal(err) + } + + automaton, err := genLR0Automaton(gram.productionSet, gram.augmentedStartSymbol) + if err != nil { + t.Fatalf("failed to create a LR0 automaton: %v", err) + } + if automaton == nil { + t.Fatalf("genLR0Automaton returns nil without any error") + } + + initialState := automaton.states[automaton.initialState] + if initialState == nil { + t.Errorf("failed to get an initial status: %v", automaton.initialState) + } + + genSym := newTestSymbolGenerator(t, gram.symbolTable) + genProd := newTestProductionGenerator(t, genSym) + genLR0Item := newTestLR0ItemGenerator(t, genProd) + + expectedKernels := map[int][]*lrItem{ + 0: { + genLR0Item("expr'", 0, "expr"), + }, + 1: { + genLR0Item("expr'", 1, "expr"), + genLR0Item("expr", 1, "expr", "add", "term"), + }, + 2: { + genLR0Item("expr", 1, "term"), + genLR0Item("term", 1, "term", "mul", "factor"), + }, + 3: { + genLR0Item("term", 1, "factor"), + }, + 4: { + genLR0Item("factor", 1, "l_paren", "expr", "r_paren"), + }, + 5: { + genLR0Item("factor", 1, "id"), + }, + 6: { + genLR0Item("expr", 2, "expr", "add", "term"), + }, + 7: { + genLR0Item("term", 2, "term", "mul", "factor"), + }, + 8: { + genLR0Item("expr", 1, "expr", "add", "term"), + genLR0Item("factor", 2, "l_paren", "expr", "r_paren"), + }, + 9: { + genLR0Item("expr", 3, "expr", "add", "term"), + genLR0Item("term", 1, "term", "mul", "factor"), + }, + 10: { + genLR0Item("term", 3, "term", "mul", "factor"), + }, + 11: { + genLR0Item("factor", 3, "l_paren", "expr", "r_paren"), + }, + } + + expectedStates := []expectedLR0State{ + { + kernelItems: expectedKernels[0], + nextStates: map[symbol][]*lrItem{ + genSym("expr"): expectedKernels[1], + genSym("term"): expectedKernels[2], + genSym("factor"): expectedKernels[3], + genSym("l_paren"): expectedKernels[4], + genSym("id"): expectedKernels[5], + }, + reducibleProds: []*production{}, + }, + { + kernelItems: expectedKernels[1], + nextStates: map[symbol][]*lrItem{ + genSym("add"): expectedKernels[6], + }, + reducibleProds: []*production{ + genProd("expr'", "expr"), + }, + }, + { + kernelItems: expectedKernels[2], + nextStates: map[symbol][]*lrItem{ + genSym("mul"): expectedKernels[7], + }, + reducibleProds: []*production{ + genProd("expr", "term"), + }, + }, + { + kernelItems: expectedKernels[3], + nextStates: map[symbol][]*lrItem{}, + reducibleProds: []*production{ + genProd("term", "factor"), + }, + }, + { + kernelItems: expectedKernels[4], + nextStates: map[symbol][]*lrItem{ + genSym("expr"): expectedKernels[8], + genSym("term"): expectedKernels[2], + genSym("factor"): expectedKernels[3], + genSym("l_paren"): expectedKernels[4], + genSym("id"): expectedKernels[5], + }, + reducibleProds: []*production{}, + }, + { + kernelItems: expectedKernels[5], + nextStates: map[symbol][]*lrItem{}, + reducibleProds: []*production{ + genProd("factor", "id"), + }, + }, + { + kernelItems: expectedKernels[6], + nextStates: map[symbol][]*lrItem{ + genSym("term"): expectedKernels[9], + genSym("factor"): expectedKernels[3], + genSym("l_paren"): expectedKernels[4], + genSym("id"): expectedKernels[5], + }, + reducibleProds: []*production{}, + }, + { + kernelItems: expectedKernels[7], + nextStates: map[symbol][]*lrItem{ + genSym("factor"): expectedKernels[10], + genSym("l_paren"): expectedKernels[4], + genSym("id"): expectedKernels[5], + }, + reducibleProds: []*production{}, + }, + { + kernelItems: expectedKernels[8], + nextStates: map[symbol][]*lrItem{ + genSym("add"): expectedKernels[6], + genSym("r_paren"): expectedKernels[11], + }, + reducibleProds: []*production{}, + }, + { + kernelItems: expectedKernels[9], + nextStates: map[symbol][]*lrItem{ + genSym("mul"): expectedKernels[7], + }, + reducibleProds: []*production{ + genProd("expr", "expr", "add", "term"), + }, + }, + { + kernelItems: expectedKernels[10], + nextStates: map[symbol][]*lrItem{}, + reducibleProds: []*production{ + genProd("term", "term", "mul", "factor"), + }, + }, + { + kernelItems: expectedKernels[11], + nextStates: map[symbol][]*lrItem{}, + reducibleProds: []*production{ + genProd("factor", "l_paren", "expr", "r_paren"), + }, + }, + } + + if len(automaton.states) != len(expectedStates) { + t.Errorf("state count is mismatched; want: %v, got: %v", len(expectedStates), len(automaton.states)) + } + + for i, eState := range expectedStates { + t.Run(fmt.Sprintf("state #%v", i), func(t *testing.T) { + k, err := newKernel(eState.kernelItems) + if err != nil { + t.Fatalf("failed to create a kernel item: %v", err) + } + + state, ok := automaton.states[k.id] + if !ok { + t.Fatalf("a kernel was not found: %v", k.id) + } + + // test next states + { + if len(state.next) != len(eState.nextStates) { + t.Errorf("next state count is mismcthed; want: %v, got: %v", len(eState.nextStates), len(state.next)) + } + for eSym, eKItems := range eState.nextStates { + nextStateKernel, err := newKernel(eKItems) + if err != nil { + t.Fatalf("failed to create a kernel item: %v", err) + } + nextState, ok := state.next[eSym] + if !ok { + t.Fatalf("next state was not found; state: %v, symbol: %v (%v)", state.id, "expr", eSym) + } + if nextState != nextStateKernel.id { + t.Fatalf("a kernel ID of the next state is mismatched; want: %v, got: %v", nextStateKernel.id, nextState) + } + } + } + + // test reducible productions + { + if len(state.reducible) != len(eState.reducibleProds) { + t.Errorf("reducible production count is mismatched; want: %v, got: %v", len(eState.reducibleProds), len(state.reducible)) + } + for _, eProd := range eState.reducibleProds { + if _, ok := state.reducible[eProd.id]; !ok { + t.Errorf("reducible production was not found: %v", eProd.id) + } + } + } + }) + } +} |