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-rw-r--r--tests/unit/urubu/driver/parser.go1972
1 files changed, 1972 insertions, 0 deletions
diff --git a/tests/unit/urubu/driver/parser.go b/tests/unit/urubu/driver/parser.go
new file mode 100644
index 0000000..31fec45
--- /dev/null
+++ b/tests/unit/urubu/driver/parser.go
@@ -0,0 +1,1972 @@
+package parser
+
+import (
+ "fmt"
+ "sort"
+ "strings"
+ "testing"
+
+ "urubu/grammar"
+ spec "urubu/spec/grammar"
+ "urubu/spec/grammar/parser"
+)
+
+func TestParserWithConflicts(t *testing.T) {
+ tests := []struct {
+ caption string
+ specSrc string
+ src string
+ cst *Node
+ }{
+ {
+ caption: "when a shift/reduce conflict occurred, we prioritize the shift action",
+ specSrc: `
+#name test;
+
+expr
+ : expr assign expr
+ | id
+ ;
+
+id: "[A-Za-z0-9_]+";
+assign: '=';
+`,
+ src: `foo=bar=baz`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "foo"),
+ ),
+ termNode("assign", "="),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "bar"),
+ ),
+ termNode("assign", "="),
+ nonTermNode("expr",
+ termNode("id", "baz"),
+ ),
+ ),
+ ),
+ },
+ {
+ caption: "when a reduce/reduce conflict occurred, we prioritize the production defined earlier in the grammar",
+ specSrc: `
+#name test;
+
+s
+ : a
+ | b
+ ;
+a
+ : id
+ ;
+b
+ : id
+ ;
+
+id: "[A-Za-z0-9_]+";
+`,
+ src: `foo`,
+ cst: nonTermNode("s",
+ nonTermNode("a",
+ termNode("id", "foo"),
+ ),
+ ),
+ },
+ {
+ caption: "left associativities defined earlier in the grammar have higher precedence",
+ specSrc: `
+#name test;
+
+#prec (
+ #left mul
+ #left add
+);
+
+expr
+ : expr add expr
+ | expr mul expr
+ | id
+ ;
+
+id: "[A-Za-z0-9_]+";
+add: '+';
+mul: '*';
+`,
+ src: `a+b*c*d+e`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "a"),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "b"),
+ ),
+ termNode("mul", "*"),
+ nonTermNode("expr",
+ termNode("id", "c"),
+ ),
+ ),
+ termNode("mul", "*"),
+ nonTermNode("expr",
+ termNode("id", "d"),
+ ),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ termNode("id", "e"),
+ ),
+ ),
+ },
+ {
+ caption: "left associativities defined in the same line have the same precedence",
+ specSrc: `
+#name test;
+
+#prec (
+ #left add sub
+);
+
+expr
+ : expr add expr
+ | expr sub expr
+ | id
+ ;
+
+id: "[A-Za-z0-9_]+";
+add: '+';
+sub: '-';
+`,
+ src: `a-b+c+d-e`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "a"),
+ ),
+ termNode("sub", "-"),
+ nonTermNode("expr",
+ termNode("id", "b"),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ termNode("id", "c"),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ termNode("id", "d"),
+ ),
+ ),
+ termNode("sub", "-"),
+ nonTermNode("expr",
+ termNode("id", "e"),
+ ),
+ ),
+ },
+ {
+ caption: "right associativities defined earlier in the grammar have higher precedence",
+ specSrc: `
+#name test;
+
+#prec (
+ #right r1
+ #right r2
+);
+
+expr
+ : expr r2 expr
+ | expr r1 expr
+ | id
+ ;
+
+whitespaces #skip
+ : "[\u{0009}\u{0020}]+";
+r1
+ : 'r1';
+r2
+ : 'r2';
+id
+ : "[A-Za-z0-9_]+";
+`,
+ src: `a r2 b r1 c r1 d r2 e`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "a"),
+ ),
+ termNode("r2", "r2"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "b"),
+ ),
+ termNode("r1", "r1"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "c"),
+ ),
+ termNode("r1", "r1"),
+ nonTermNode("expr",
+ termNode("id", "d"),
+ ),
+ ),
+ ),
+ termNode("r2", "r2"),
+ nonTermNode("expr",
+ termNode("id", "e"),
+ ),
+ ),
+ ),
+ },
+ {
+ caption: "right associativities defined in the same line have the same precedence",
+ specSrc: `
+#name test;
+
+#prec (
+ #right r1 r2
+);
+
+expr
+ : expr r2 expr
+ | expr r1 expr
+ | id
+ ;
+
+whitespaces #skip
+ : "[\u{0009}\u{0020}]+";
+r1
+ : 'r1';
+r2
+ : 'r2';
+id
+ : "[A-Za-z0-9_]+";
+`,
+ src: `a r2 b r1 c r1 d r2 e`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "a"),
+ ),
+ termNode("r2", "r2"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "b"),
+ ),
+ termNode("r1", "r1"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "c"),
+ ),
+ termNode("r1", "r1"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "d"),
+ ),
+ termNode("r2", "r2"),
+ nonTermNode("expr",
+ termNode("id", "e"),
+ ),
+ ),
+ ),
+ ),
+ ),
+ },
+ {
+ caption: "terminal symbols with an #assign directive defined earlier in the grammar have higher precedence",
+ specSrc: `
+#name test;
+
+#prec (
+ #assign a1
+ #assign a2
+);
+
+expr
+ : expr a2 expr
+ | expr a1 expr
+ | id
+ ;
+
+whitespaces #skip
+ : "[\u{0009}\u{0020}]+";
+a1
+ : 'a1';
+a2
+ : 'a2';
+id
+ : "[A-Za-z0-9_]+";
+`,
+ src: `a a2 b a1 c a1 d a2 e`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "a"),
+ ),
+ termNode("a2", "a2"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "b"),
+ ),
+ termNode("a1", "a1"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "c"),
+ ),
+ termNode("a1", "a1"),
+ nonTermNode("expr",
+ termNode("id", "d"),
+ ),
+ ),
+ ),
+ termNode("a2", "a2"),
+ nonTermNode("expr",
+ termNode("id", "e"),
+ ),
+ ),
+ ),
+ },
+ {
+ caption: "terminal symbols with an #assign directive defined in the same line have the same precedence",
+ specSrc: `
+#name test;
+
+#prec (
+ #assign a1 a2
+);
+
+expr
+ : expr a2 expr
+ | expr a1 expr
+ | id
+ ;
+
+whitespaces #skip
+ : "[\u{0009}\u{0020}]+";
+a1
+ : 'a1';
+a2
+ : 'a2';
+id
+ : "[A-Za-z0-9_]+";
+`,
+ src: `a a2 b a1 c a1 d a2 e`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "a"),
+ ),
+ termNode("a2", "a2"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "b"),
+ ),
+ termNode("a1", "a1"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "c"),
+ ),
+ termNode("a1", "a1"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "d"),
+ ),
+ termNode("a2", "a2"),
+ nonTermNode("expr",
+ termNode("id", "e"),
+ ),
+ ),
+ ),
+ ),
+ ),
+ },
+ {
+ caption: "#left, #right, and #assign can be mixed",
+ specSrc: `
+#name test;
+
+#prec (
+ #left mul div
+ #left add sub
+ #assign else
+ #assign then
+ #right assign
+);
+
+expr
+ : expr add expr
+ | expr sub expr
+ | expr mul expr
+ | expr div expr
+ | expr assign expr
+ | if expr then expr
+ | if expr then expr else expr
+ | id
+ ;
+
+ws #skip: "[\u{0009}\u{0020}]+";
+if: 'if';
+then: 'then';
+else: 'else';
+id: "[A-Za-z0-9_]+";
+add: '+';
+sub: '-';
+mul: '*';
+div: '/';
+assign: '=';
+`,
+ src: `x = y = a + b * c - d / e + if f then if g then h else i`,
+ cst: nonTermNode(
+ "expr",
+ nonTermNode("expr",
+ termNode("id", "x"),
+ ),
+ termNode("assign", "="),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "y"),
+ ),
+ termNode("assign", "="),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "a"),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "b"),
+ ),
+ termNode("mul", "*"),
+ nonTermNode("expr",
+ termNode("id", "c"),
+ ),
+ ),
+ ),
+ termNode("sub", "-"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("id", "d"),
+ ),
+ termNode("div", "/"),
+ nonTermNode("expr",
+ termNode("id", "e"),
+ ),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ termNode("if", "if"),
+ nonTermNode("expr",
+ termNode("id", "f"),
+ ),
+ termNode("then", "then"),
+ nonTermNode("expr",
+ termNode("if", "if"),
+ nonTermNode("expr",
+ termNode("id", "g"),
+ ),
+ termNode("then", "then"),
+ nonTermNode("expr",
+ termNode("id", "h"),
+ ),
+ termNode("else", "else"),
+ nonTermNode("expr",
+ termNode("id", "i"),
+ ),
+ ),
+ ),
+ ),
+ ),
+ ),
+ },
+ }
+
+ 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,
+ }
+ cg, _, err := b.Build()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ toks, err := NewTokenStream(cg, strings.NewReader(tt.src))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ gram := NewGrammar(cg)
+ tb := NewDefaultSyntaxTreeBuilder()
+ p, err := NewParser(toks, gram, SemanticAction(NewCSTActionSet(gram, tb)))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ err = p.Parse()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ if tt.cst != nil {
+ testTree(t, tb.Tree(), tt.cst)
+ }
+ })
+ }
+}
+
+func TestParserWithLAC(t *testing.T) {
+ specSrc := `
+#name test;
+
+s
+ : t t
+ ;
+t
+ : c t
+ | d
+ ;
+
+c: 'c';
+d: 'd';
+`
+
+ src := `ccd`
+
+ actLogWithLAC := []string{
+ "shift/c",
+ "shift/c",
+ "shift/d",
+ "miss",
+ }
+
+ actLogWithoutLAC := []string{
+ "shift/c",
+ "shift/c",
+ "shift/d",
+ "reduce/t",
+ "reduce/t",
+ "reduce/t",
+ "miss",
+ }
+
+ ast, err := parser.Parse(strings.NewReader(specSrc))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ b := grammar.GrammarBuilder{
+ AST: ast,
+ }
+ gram, _, err := b.Build()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ t.Run("LAC is enabled", func(t *testing.T) {
+ semAct := &testSemAct{
+ gram: gram,
+ }
+
+ toks, err := NewTokenStream(gram, strings.NewReader(src))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ 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(actLogWithLAC) {
+ t.Fatalf("unexpected action log; want: %+v, got: %+v", actLogWithLAC, semAct.actLog)
+ }
+
+ for i, e := range actLogWithLAC {
+ if semAct.actLog[i] != e {
+ t.Fatalf("unexpected action log; want: %+v, got: %+v", actLogWithLAC, semAct.actLog)
+ }
+ }
+ })
+
+ t.Run("LAC is disabled", func(t *testing.T) {
+ semAct := &testSemAct{
+ gram: gram,
+ }
+
+ toks, err := NewTokenStream(gram, strings.NewReader(src))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ p, err := NewParser(toks, NewGrammar(gram), SemanticAction(semAct), DisableLAC())
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ err = p.Parse()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ if len(semAct.actLog) != len(actLogWithoutLAC) {
+ t.Fatalf("unexpected action log; want: %+v, got: %+v", actLogWithoutLAC, semAct.actLog)
+ }
+
+ for i, e := range actLogWithoutLAC {
+ if semAct.actLog[i] != e {
+ t.Fatalf("unexpected action log; want: %+v, got: %+v", actLogWithoutLAC, semAct.actLog)
+ }
+ }
+ })
+}
+
+func termNode(kind string, text string, children ...*Node) *Node {
+ return &Node{
+ Type: NodeTypeTerminal,
+ KindName: kind,
+ Text: text,
+ Children: children,
+ }
+}
+
+func errorNode() *Node {
+ return &Node{
+ Type: NodeTypeError,
+ KindName: "error",
+ }
+}
+
+func nonTermNode(kind string, children ...*Node) *Node {
+ return &Node{
+ Type: NodeTypeNonTerminal,
+ KindName: kind,
+ Children: children,
+ }
+}
+
+func TestParser_Parse(t *testing.T) {
+ tests := []struct {
+ specSrc string
+ src string
+ synErr bool
+ cst *Node
+ ast *Node
+ }{
+ {
+ specSrc: `
+#name test;
+
+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_]*";
+`,
+ src: `(a+(b+c))*d+e`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("term",
+ nonTermNode("term",
+ nonTermNode("factor",
+ termNode("l_paren", "("),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("term",
+ nonTermNode("factor",
+ termNode("id", "a"),
+ ),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("term",
+ nonTermNode("factor",
+ termNode("l_paren", "("),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("term",
+ nonTermNode("factor",
+ termNode("id", "b"),
+ ),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("term",
+ nonTermNode("factor",
+ termNode("id", "c"),
+ ),
+ ),
+ ),
+ termNode("r_paren", ")"),
+ ),
+ ),
+ ),
+ termNode("r_paren", ")"),
+ ),
+ ),
+ termNode("mul", "*"),
+ nonTermNode("factor",
+ termNode("id", "d"),
+ ),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("term",
+ nonTermNode("factor",
+ termNode("id", "e"),
+ ),
+ ),
+ ),
+ },
+ // Fragments (\f{}), code point expressions (\u{}), and character property expressions (\p{}) are
+ // not allowed in string literals.
+ {
+ specSrc: `
+#name test;
+
+s
+ : a b c
+ ;
+
+a
+ : '\f{foo}';
+b
+ : '\u{0000}';
+c
+ : '\p{gc=Letter}';
+`,
+ src: `\f{foo}\u{0000}\p{gc=Letter}`,
+ cst: nonTermNode("s",
+ termNode("a", `\f{foo}`),
+ termNode("b", `\u{0000}`),
+ termNode("c", `\p{gc=Letter}`),
+ ),
+ },
+ // The driver can reduce productions that have the empty alternative and can generate a CST (and AST) node.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo bar
+ ;
+foo
+ :
+ ;
+bar
+ : bar_text
+ |
+ ;
+bar_text: "bar";
+`,
+ src: ``,
+ cst: nonTermNode("s",
+ nonTermNode("foo"),
+ nonTermNode("bar"),
+ ),
+ },
+ // The driver can reduce productions that have the empty alternative and can generate a CST (and AST) node.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo bar
+ ;
+foo
+ :
+ ;
+bar
+ : bar_text
+ |
+ ;
+
+bar_text
+ : "bar";
+`,
+ src: `bar`,
+ cst: nonTermNode("s",
+ nonTermNode("foo"),
+ nonTermNode("bar",
+ termNode("bar_text", "bar"),
+ ),
+ ),
+ },
+ // A production can have multiple alternative productions.
+ {
+ specSrc: `
+#name test;
+
+#prec (
+ #assign $uminus
+ #left mul div
+ #left add sub
+);
+
+expr
+ : expr add expr
+ | expr sub expr
+ | expr mul expr
+ | expr div expr
+ | int
+ | sub int #prec $uminus // This 'sub' means the unary minus symbol.
+ ;
+
+int
+ : "0|[1-9][0-9]*";
+add
+ : '+';
+sub
+ : '-';
+mul
+ : '*';
+div
+ : '/';
+`,
+ src: `-1*-2+3-4/5`,
+ ast: nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("sub", "-"),
+ termNode("int", "1"),
+ ),
+ termNode("mul", "*"),
+ nonTermNode("expr",
+ termNode("sub", "-"),
+ termNode("int", "2"),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ termNode("int", "3"),
+ ),
+ ),
+ termNode("sub", "-"),
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("int", "4"),
+ ),
+ termNode("div", "/"),
+ nonTermNode("expr",
+ termNode("int", "5"),
+ ),
+ ),
+ ),
+ },
+ // A lexical production can have multiple production directives.
+ {
+ specSrc: `
+#name test;
+
+s
+ : push_a push_b pop pop
+ ;
+
+push_a #mode default #push a
+ : '->a';
+push_b #mode a #push b
+ : '->b';
+pop #mode a b #pop
+ : '<-';
+`,
+ src: `->a->b<-<-`,
+ ast: nonTermNode("s",
+ termNode("push_a", "->a"),
+ termNode("push_b", "->b"),
+ termNode("pop", "<-"),
+ termNode("pop", "<-"),
+ ),
+ },
+ {
+ specSrc: `
+#name test;
+
+mode_tran_seq
+ : mode_tran_seq mode_tran
+ | mode_tran
+ ;
+mode_tran
+ : push_m1
+ | push_m2
+ | pop_m1
+ | pop_m2
+ ;
+
+push_m1 #push m1
+ : "->";
+push_m2 #mode m1 #push m2
+ : "-->";
+pop_m1 #mode m1 #pop
+ : "<-";
+pop_m2 #mode m2 #pop
+ : "<--";
+whitespace #mode default m1 m2 #skip
+ : "\u{0020}+";
+`,
+ src: ` -> --> <-- <- `,
+ },
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo bar
+ ;
+
+foo
+ : "foo";
+bar #mode default
+ : "bar";
+`,
+ src: `foobar`,
+ },
+ // When #push and #pop are applied to the same symbol, #pop will run first, then #push.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo bar baz
+ ;
+
+foo #push m1
+ : 'foo';
+bar #mode m1 #pop #push m2
+ : 'bar';
+baz #mode m2
+ : 'baz';
+`,
+ src: `foobarbaz`,
+ ast: nonTermNode("s",
+ termNode("foo", "foo"),
+ termNode("bar", "bar"),
+ termNode("baz", "baz"),
+ ),
+ },
+ // When #push and #pop are applied to the same symbol, #pop will run first, then #push, even if #push appears first
+ // in a definition. That is, the order in which #push and #pop appear in grammar has nothing to do with the order in which
+ // they are executed.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo bar baz
+ ;
+
+foo #push m1
+ : 'foo';
+bar #mode m1 #push m2 #pop
+ : 'bar';
+baz #mode m2
+ : 'baz';
+`,
+ src: `foobarbaz`,
+ ast: nonTermNode("s",
+ termNode("foo", "foo"),
+ termNode("bar", "bar"),
+ termNode("baz", "baz"),
+ ),
+ },
+ // The parser can skips specified tokens.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo bar
+ ;
+
+foo
+ : "foo";
+bar
+ : "bar";
+white_space #skip
+ : "[\u{0009}\u{0020}]+";
+`,
+ src: `foo bar`,
+ },
+ // A grammar can contain fragments.
+ {
+ specSrc: `
+#name test;
+
+s
+ : tagline
+ ;
+tagline
+ : "\f{words} IS OUT THERE.";
+fragment words
+ : "[A-Za-z\u{0020}]+";
+`,
+ src: `THE TRUTH IS OUT THERE.`,
+ },
+ // A grammar can contain ast actions.
+ {
+ specSrc: `
+#name test;
+
+list
+ : l_bracket elems r_bracket #ast elems...
+ ;
+elems
+ : elems comma id #ast elems... id
+ | id
+ ;
+
+whitespace #skip
+ : "\u{0020}+";
+l_bracket
+ : '[';
+r_bracket
+ : ']';
+comma
+ : ',';
+id
+ : "[A-Za-z]+";
+`,
+ src: `[Byers, Frohike, Langly]`,
+ cst: nonTermNode("list",
+ termNode("x_1", "["),
+ nonTermNode("elems",
+ nonTermNode("elems",
+ nonTermNode("elems",
+ termNode("id", "Byers"),
+ ),
+ termNode("x_3", ","),
+ termNode("id", "Frohike"),
+ ),
+ termNode("x_3", ","),
+ termNode("id", "Langly"),
+ ),
+ termNode("x_2", "]"),
+ ),
+ ast: nonTermNode("list",
+ termNode("id", "Byers"),
+ termNode("id", "Frohike"),
+ termNode("id", "Langly"),
+ ),
+ },
+ // The '...' operator can expand child nodes.
+ {
+ specSrc: `
+#name test;
+
+s
+ : a #ast a...
+ ;
+a
+ : a comma foo #ast a... foo
+ | foo
+ ;
+
+comma
+ : ',';
+foo
+ : 'foo';
+`,
+ src: `foo,foo,foo`,
+ ast: nonTermNode("s",
+ termNode("foo", "foo"),
+ termNode("foo", "foo"),
+ termNode("foo", "foo"),
+ ),
+ },
+ // The '...' operator also can applied to an element having no children.
+ {
+ specSrc: `
+#name test;
+
+s
+ : a semi_colon #ast a...
+ ;
+a
+ :
+ ;
+
+semi_colon
+ : ';';
+`,
+ src: `;`,
+ ast: nonTermNode("s"),
+ },
+ // A label can be a parameter of #ast directive.
+ {
+ specSrc: `
+#name test;
+
+#prec (
+ #left add sub
+);
+
+expr
+ : expr@lhs add expr@rhs #ast add lhs rhs
+ | expr@lhs sub expr@rhs #ast sub lhs rhs
+ | num
+ ;
+
+add
+ : '+';
+sub
+ : '-';
+num
+ : "0|[1-9][0-9]*";
+`,
+ src: `1+2-3`,
+ ast: nonTermNode("expr",
+ termNode("sub", "-"),
+ nonTermNode("expr",
+ termNode("add", "+"),
+ nonTermNode("expr",
+ termNode("num", "1"),
+ ),
+ nonTermNode("expr",
+ termNode("num", "2"),
+ ),
+ ),
+ nonTermNode("expr",
+ termNode("num", "3"),
+ ),
+ ),
+ },
+ // An AST can contain a symbol name, even if the symbol has a label. That is, unused labels are allowed.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo@x semi_colon #ast foo
+ ;
+
+semi_colon
+ : ';';
+foo
+ : 'foo';
+`,
+ src: `foo;`,
+ ast: nonTermNode("s",
+ termNode("foo", "foo"),
+ ),
+ },
+ // A production has the same precedence and associativity as the right-most terminal symbol.
+ {
+ specSrc: `
+#name test;
+
+#prec (
+ #left add
+);
+
+expr
+ : expr add expr // This alternative has the same precedence and associativiry as 'add'.
+ | int
+ ;
+
+ws #skip
+ : "[\u{0009}\u{0020}]+";
+int
+ : "0|[1-9][0-9]*";
+add
+ : '+';
+`,
+ // This source is recognized as the following structure because the production `expr → expr add expr` has the same
+ // precedence and associativity as the symbol 'add'.
+ //
+ // ((1+2)+3)
+ //
+ // If the symbol doesn't have the precedence and left associativity, the production also doesn't have the precedence
+ // and associativity and this source will be recognized as the following structure.
+ //
+ // (1+(2+3))
+ src: `1+2+3`,
+ ast: nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("int", "1"),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ termNode("int", "2"),
+ ),
+ ),
+ termNode("add", "+"),
+ nonTermNode("expr",
+ termNode("int", "3"),
+ ),
+ ),
+ },
+ // The 'prec' directive can set precedence of a production.
+ {
+ specSrc: `
+#name test;
+
+#prec (
+ #assign $uminus
+ #left mul div
+ #left add sub
+);
+
+expr
+ : expr add expr
+ | expr sub expr
+ | expr mul expr
+ | expr div expr
+ | int
+ | sub int #prec $uminus // This 'sub' means a unary minus symbol.
+ ;
+
+ws #skip
+ : "[\u{0009}\u{0020}]+";
+int
+ : "0|[1-9][0-9]*";
+add
+ : '+';
+sub
+ : '-';
+mul
+ : '*';
+div
+ : '/';
+`,
+ // This source is recognized as the following structure because the production `expr → sub expr`
+ // has the `#prec mul` directive and has the same precedence of the symbol `mul`.
+ //
+ // (((-1) * 20) / 5)
+ //
+ // If the production doesn't have the `#prec` directive, this source will be recognized as
+ // the following structure.
+ //
+ // (- ((1 * 20) / 5))
+ src: `-1*20/5`,
+ cst: nonTermNode("expr",
+ nonTermNode("expr",
+ nonTermNode("expr",
+ termNode("sub", "-"),
+ termNode("int", "1"),
+ ),
+ termNode("mul", "*"),
+ nonTermNode("expr",
+ termNode("int", "20"),
+ ),
+ ),
+ termNode("div", "/"),
+ nonTermNode("expr",
+ termNode("int", "5"),
+ ),
+ ),
+ },
+ // The grammar can contain the 'error' symbol.
+ {
+ specSrc: `
+#name test;
+
+s
+ : id id id semi_colon
+ | error semi_colon
+ ;
+
+ws #skip
+ : "[\u{0009}\u{0020}]+";
+semi_colon
+ : ';';
+id
+ : "[A-Za-z_]+";
+`,
+ src: `foo bar baz ;`,
+ },
+ // The 'error' symbol can appear in an #ast directive.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo semi_colon
+ | error semi_colon #ast error
+ ;
+
+semi_colon
+ : ';';
+foo
+ : 'foo';
+`,
+ src: `bar;`,
+ synErr: true,
+ ast: nonTermNode("s",
+ errorNode(),
+ ),
+ },
+ // The 'error' symbol can have a label, and an #ast can reference it.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo semi_colon
+ | error@e semi_colon #ast e
+ ;
+
+semi_colon
+ : ';';
+foo
+ : 'foo';
+`,
+ src: `bar;`,
+ synErr: true,
+ ast: nonTermNode("s",
+ errorNode(),
+ ),
+ },
+ // The grammar can contain the 'recover' directive.
+ {
+ specSrc: `
+#name test;
+
+seq
+ : seq elem
+ | elem
+ ;
+elem
+ : id id id semi_colon
+ | error semi_colon #recover
+ ;
+
+ws #skip
+ : "[\u{0009}\u{0020}]+";
+semi_colon
+ : ';';
+id
+ : "[A-Za-z_]+";
+`,
+ src: `a b c ; d e f ;`,
+ },
+ // The same label can be used between different alternatives.
+ {
+ specSrc: `
+#name test;
+
+s
+ : foo@x bar
+ | foo@x
+ ;
+
+foo: 'foo';
+bar: 'bar';
+`,
+ src: `foo`,
+ },
+ }
+
+ for i, tt := range tests {
+ t.Run(fmt.Sprintf("#%v", i), func(t *testing.T) {
+ ast, err := parser.Parse(strings.NewReader(tt.specSrc))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ b := grammar.GrammarBuilder{
+ AST: ast,
+ }
+ cg, _, err := b.Build()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ toks, err := NewTokenStream(cg, strings.NewReader(tt.src))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ gram := NewGrammar(cg)
+ tb := NewDefaultSyntaxTreeBuilder()
+ var opt []ParserOption
+ switch {
+ case tt.ast != nil:
+ opt = append(opt, SemanticAction(NewASTActionSet(gram, tb)))
+ case tt.cst != nil:
+ opt = append(opt, SemanticAction(NewCSTActionSet(gram, tb)))
+ }
+ p, err := NewParser(toks, gram, opt...)
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ err = p.Parse()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ if !tt.synErr && len(p.SyntaxErrors()) > 0 {
+ for _, synErr := range p.SyntaxErrors() {
+ t.Fatalf("unexpected syntax errors occurred: %v", synErr)
+ }
+ }
+
+ switch {
+ case tt.ast != nil:
+ testTree(t, tb.Tree(), tt.ast)
+ case tt.cst != nil:
+ testTree(t, tb.Tree(), tt.cst)
+ }
+ })
+ }
+}
+
+func testTree(t *testing.T, node, expected *Node) {
+ t.Helper()
+
+ if node.Type != expected.Type || node.KindName != expected.KindName || node.Text != expected.Text {
+ t.Fatalf("unexpected node; want: %+v, got: %+v", expected, node)
+ }
+ if len(node.Children) != len(expected.Children) {
+ t.Fatalf("unexpected children; want: %v, got: %v", len(expected.Children), len(node.Children))
+ }
+ for i, c := range node.Children {
+ testTree(t, c, expected.Children[i])
+ }
+}
+
+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)
+ }
+ }
+ })
+ }
+}
+
+func TestParserWithSyntaxErrors(t *testing.T) {
+ tests := []struct {
+ caption string
+ specSrc string
+ src string
+ synErrCount int
+ }{
+ {
+ caption: "the parser can report a syntax error",
+ specSrc: `
+#name test;
+
+s
+ : foo
+ ;
+
+foo
+ : 'foo';
+`,
+ src: `bar`,
+ synErrCount: 1,
+ },
+ {
+ caption: "when the parser reduced a production having the reduce directive, the parser will recover from an error state",
+ specSrc: `
+#name test;
+
+seq
+ : seq elem semi_colon
+ | elem semi_colon
+ | error semi_colon #recover
+ ;
+elem
+ : a b c
+ ;
+
+ws #skip
+ : "[\u{0009}\u{0020}]+";
+semi_colon
+ : ';';
+a
+ : 'a';
+b
+ : 'b';
+c
+ : 'c';
+`,
+ src: `!; a!; ab!;`,
+ synErrCount: 3,
+ },
+ {
+ caption: "After the parser shifts the error symbol, symbols are ignored until a symbol the parser can perform shift appears",
+ specSrc: `
+#name test;
+
+seq
+ : seq elem semi_colon
+ | elem semi_colon
+ | error semi_colon #recover
+ ;
+elem
+ : a b c
+ ;
+
+ws #skip
+ : "[\u{0009}\u{0020}]+";
+semi_colon
+ : ';';
+a
+ : 'a';
+b
+ : 'b';
+c
+ : 'c';
+`,
+ // After the parser trasits to the error state reading the first invalid symbol ('!'),
+ // the second and third invalid symbols ('!') are ignored.
+ src: `! ! !; a!; ab!;`,
+ synErrCount: 3,
+ },
+ {
+ caption: "when the parser performs shift three times, the parser recovers from the error state",
+ specSrc: `
+#name test;
+
+seq
+ : seq elem semi_colon
+ | elem semi_colon
+ | error star star semi_colon
+ ;
+elem
+ : a b c
+ ;
+
+ws #skip
+ : "[\u{0009}\u{0020}]+";
+semi_colon
+ : ';';
+star
+ : '*';
+a
+ : 'a';
+b
+ : 'b';
+c
+ : 'c';
+`,
+ src: `!**; a!**; ab!**; abc!`,
+ synErrCount: 4,
+ },
+ }
+ for i, tt := range tests {
+ t.Run(fmt.Sprintf("#%v", i), 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)
+ }
+
+ p, err := NewParser(toks, NewGrammar(gram))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ err = p.Parse()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ synErrs := p.SyntaxErrors()
+ if len(synErrs) != tt.synErrCount {
+ t.Fatalf("unexpected syntax error; want: %v error(s), got: %v error(s)", tt.synErrCount, len(synErrs))
+ }
+ })
+ }
+}
+
+func TestParserWithSyntaxErrorAndExpectedLookahead(t *testing.T) {
+ tests := []struct {
+ caption string
+ specSrc string
+ src string
+ cause string
+ expected []string
+ }{
+ {
+ caption: "the parser reports an expected lookahead symbol",
+ specSrc: `
+#name test;
+
+s
+ : foo
+ ;
+
+foo
+ : 'foo';
+`,
+ src: `bar`,
+ cause: `bar`,
+ expected: []string{
+ "foo",
+ },
+ },
+ {
+ caption: "the parser reports expected lookahead symbols",
+ specSrc: `
+#name test;
+
+s
+ : foo
+ | bar
+ ;
+
+foo
+ : 'foo';
+bar
+ : 'bar';
+`,
+ src: `baz`,
+ cause: `baz`,
+ expected: []string{
+ "foo",
+ "bar",
+ },
+ },
+ {
+ caption: "the parser may report the EOF as an expected lookahead symbol",
+ specSrc: `
+#name test;
+
+s
+ : foo
+ ;
+
+foo
+ : 'foo';
+`,
+ src: `foobar`,
+ cause: `bar`,
+ expected: []string{
+ "<eof>",
+ },
+ },
+ {
+ caption: "the parser may report the EOF and others as expected lookahead symbols",
+ specSrc: `
+#name test;
+
+s
+ : foo
+ |
+ ;
+
+foo
+ : 'foo';
+`,
+ src: `bar`,
+ cause: `bar`,
+ expected: []string{
+ "foo",
+ "<eof>",
+ },
+ },
+ }
+ for i, tt := range tests {
+ t.Run(fmt.Sprintf("#%v", i), 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)
+ }
+
+ p, err := NewParser(toks, NewGrammar(gram))
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ err = p.Parse()
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ synErrs := p.SyntaxErrors()
+ if synErrs == nil {
+ t.Fatalf("expected one syntax error, but it didn't occur")
+ }
+ if len(synErrs) != 1 {
+ t.Fatalf("too many syntax errors: %v errors", len(synErrs))
+ }
+ synErr := synErrs[0]
+ if string(synErr.Token.Lexeme()) != tt.cause {
+ t.Fatalf("unexpected lexeme: want: %v, got: %v", tt.cause, string(synErr.Token.Lexeme()))
+ }
+ if len(synErr.ExpectedTerminals) != len(tt.expected) {
+ t.Fatalf("unexpected lookahead symbols: want: %v, got: %v", tt.expected, synErr.ExpectedTerminals)
+ }
+ sort.Slice(tt.expected, func(i, j int) bool {
+ return tt.expected[i] < tt.expected[j]
+ })
+ sort.Slice(synErr.ExpectedTerminals, func(i, j int) bool {
+ return synErr.ExpectedTerminals[i] < synErr.ExpectedTerminals[j]
+ })
+ for i, e := range tt.expected {
+ if synErr.ExpectedTerminals[i] != e {
+ t.Errorf("unexpected lookahead symbol: want: %v, got: %v", e, synErr.ExpectedTerminals[i])
+ }
+ }
+ })
+ }
+}
generated by cgit v1.2.3 (git 2.49.0) at 2025-07-12 23:14:44 +0000