| // Copyright 2017 The Puffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package parse |
| |
| // TODO: write a formal grammar for the language. |
| |
| import ( |
| "fmt" |
| |
| "github.com/google/puffs/lang/base38" |
| |
| a "github.com/google/puffs/lang/ast" |
| t "github.com/google/puffs/lang/token" |
| ) |
| |
| func Parse(tm *t.Map, filename string, src []t.Token) (*a.File, error) { |
| p := &parser{ |
| src: src, |
| tm: tm, |
| filename: filename, |
| } |
| if len(src) > 0 { |
| p.lastLine = src[len(src)-1].Line |
| } |
| return p.parseFile() |
| } |
| |
| func ParseExpr(tm *t.Map, filename string, src []t.Token) (*a.Expr, error) { |
| p := &parser{ |
| src: src, |
| tm: tm, |
| filename: filename, |
| } |
| if len(src) > 0 { |
| p.lastLine = src[len(src)-1].Line |
| } |
| return p.parseExpr() |
| } |
| |
| type parser struct { |
| src []t.Token |
| tm *t.Map |
| filename string |
| lastLine uint32 |
| } |
| |
| func (p *parser) line() uint32 { |
| if len(p.src) != 0 { |
| return p.src[0].Line |
| } |
| return p.lastLine |
| } |
| |
| func (p *parser) peek1() t.ID { |
| if len(p.src) > 0 { |
| return p.src[0].ID |
| } |
| return 0 |
| } |
| |
| func (p *parser) parseFile() (*a.File, error) { |
| topLevelDecls := []*a.Node(nil) |
| for len(p.src) > 0 { |
| d, err := p.parseTopLevelDecl() |
| if err != nil { |
| return nil, err |
| } |
| topLevelDecls = append(topLevelDecls, d) |
| } |
| return a.NewFile(p.filename, topLevelDecls), nil |
| } |
| |
| func (p *parser) parseTopLevelDecl() (*a.Node, error) { |
| flags := a.Flags(0) |
| line := p.src[0].Line |
| switch k := p.peek1().Key(); k { |
| case t.KeyPackageID, t.KeyUse: |
| p.src = p.src[1:] |
| path := p.peek1() |
| if !path.IsStrLiteral() { |
| got := p.tm.ByID(path) |
| return nil, fmt.Errorf(`parse: expected string literal, got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| if x := p.peek1().Key(); x != t.KeySemicolon { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected (implicit) ";", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| if k == t.KeyPackageID { |
| raw := path.String(p.tm) |
| s, ok := t.Unescape(raw) |
| if !ok { |
| return nil, fmt.Errorf(`parse: %q is not a valid packageid`, raw) |
| } |
| if u, ok := base38.Encode(s); !ok || u == 0 { |
| return nil, fmt.Errorf(`parse: %q is not a valid packageid`, s) |
| } |
| return a.NewPackageID(p.filename, line, path).Node(), nil |
| } else { |
| return a.NewUse(p.filename, line, path).Node(), nil |
| } |
| |
| case t.KeyPub: |
| flags |= a.FlagsPublic |
| fallthrough |
| case t.KeyPri: |
| p.src = p.src[1:] |
| switch p.peek1().Key() { |
| case t.KeyConst: |
| p.src = p.src[1:] |
| id, err := p.parseIdent() |
| if err != nil { |
| return nil, err |
| } |
| typ, err := p.parseTypeExpr() |
| if err != nil { |
| return nil, err |
| } |
| if p.peek1().Key() != t.KeyEq { |
| return nil, fmt.Errorf(`parse: const %q has no value at %s:%d`, |
| p.tm.ByID(id), p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| value := (*a.Expr)(nil) |
| // TODO: parse lists of lists. |
| if p.peek1().Key() == t.KeyDollar { |
| value, err = p.parseDollarExpr() |
| if err != nil { |
| return nil, err |
| } |
| } else { |
| value, err = p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| } |
| if x := p.peek1().Key(); x != t.KeySemicolon { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected (implicit) ";", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| return a.NewConst(flags, p.filename, line, id, typ, value).Node(), nil |
| |
| case t.KeyFunc: |
| p.src = p.src[1:] |
| id0, id1, err := p.parseQualifiedIdent() |
| if err != nil { |
| return nil, err |
| } |
| if id0 != 0 && id0.IsBuiltIn() { |
| return nil, fmt.Errorf(`parse: built-in %q used for func receiver at %s:%d`, |
| p.tm.ByID(id0), p.filename, p.line()) |
| } |
| if id1.IsBuiltIn() { |
| return nil, fmt.Errorf(`parse: built-in %q used for func name at %s:%d`, |
| p.tm.ByID(id1), p.filename, p.line()) |
| } |
| switch p.peek1().Key() { |
| case t.KeyExclam: |
| flags |= a.FlagsImpure |
| p.src = p.src[1:] |
| case t.KeyQuestion: |
| flags |= a.FlagsImpure | a.FlagsSuspendible |
| p.src = p.src[1:] |
| } |
| inFields, err := p.parseList(t.KeyCloseParen, (*parser).parseFieldNode) |
| if err != nil { |
| return nil, err |
| } |
| outFields, err := p.parseList(t.KeyCloseParen, (*parser).parseFieldNode) |
| if err != nil { |
| return nil, err |
| } |
| asserts := []*a.Node(nil) |
| if p.peek1().Key() == t.KeyComma { |
| p.src = p.src[1:] |
| asserts, err = p.parseList(t.KeyOpenCurly, (*parser).parseAssertNode) |
| if err != nil { |
| return nil, err |
| } |
| if err := p.assertsSorted(asserts); err != nil { |
| return nil, err |
| } |
| } |
| body, err := p.parseBlock() |
| if err != nil { |
| return nil, err |
| } |
| if x := p.peek1().Key(); x != t.KeySemicolon { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected (implicit) ";", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| in := a.NewStruct(0, p.filename, line, t.IDIn, inFields) |
| out := a.NewStruct(0, p.filename, line, t.IDOut, outFields) |
| return a.NewFunc(flags, p.filename, line, id0, id1, in, out, asserts, body).Node(), nil |
| |
| case t.KeyError, t.KeySuspension: |
| keyword := p.src[0].ID |
| p.src = p.src[1:] |
| message := p.peek1() |
| if !message.IsStrLiteral() { |
| got := p.tm.ByID(message) |
| return nil, fmt.Errorf(`parse: expected string literal, got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| if x := p.peek1().Key(); x != t.KeySemicolon { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected (implicit) ";", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| return a.NewStatus(flags, p.filename, line, keyword, message).Node(), nil |
| |
| case t.KeyStruct: |
| p.src = p.src[1:] |
| name, err := p.parseIdent() |
| if err != nil { |
| return nil, err |
| } |
| if name.IsBuiltIn() { |
| return nil, fmt.Errorf(`parse: built-in %q used for struct name at %s:%d`, |
| p.tm.ByID(name), p.filename, p.line()) |
| } |
| if p.peek1().Key() == t.KeyQuestion { |
| flags |= a.FlagsSuspendible |
| p.src = p.src[1:] |
| } |
| fields, err := p.parseList(t.KeyCloseParen, (*parser).parseFieldNode) |
| if err != nil { |
| return nil, err |
| } |
| if x := p.peek1().Key(); x != t.KeySemicolon { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected (implicit) ";", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| return a.NewStruct(flags, p.filename, line, name, fields).Node(), nil |
| } |
| } |
| return nil, fmt.Errorf(`parse: unrecognized top level declaration at %s:%d`, p.filename, line) |
| } |
| |
| // parseQualifiedIdent parses "foo.bar" or "bar". |
| func (p *parser) parseQualifiedIdent() (t.ID, t.ID, error) { |
| x, err := p.parseIdent() |
| if err != nil { |
| return 0, 0, err |
| } |
| |
| if p.peek1().Key() != t.KeyDot { |
| return 0, x, nil |
| } |
| p.src = p.src[1:] |
| |
| y, err := p.parseIdent() |
| if err != nil { |
| return 0, 0, err |
| } |
| return x, y, nil |
| } |
| |
| func (p *parser) parseIdent() (t.ID, error) { |
| if len(p.src) == 0 { |
| return 0, fmt.Errorf(`parse: expected identifier at %s:%d`, p.filename, p.line()) |
| } |
| x := p.src[0] |
| if !x.IsIdent() { |
| got := p.tm.ByToken(x) |
| return 0, fmt.Errorf(`parse: expected identifier, got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| return x.ID, nil |
| } |
| |
| func (p *parser) parseList(stop t.Key, parseElem func(*parser) (*a.Node, error)) ([]*a.Node, error) { |
| if stop == t.KeyCloseParen { |
| if x := p.peek1().Key(); x != t.KeyOpenParen { |
| return nil, fmt.Errorf(`parse: expected "(", got %q at %s:%d`, |
| p.tm.ByKey(x), p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| } |
| |
| ret := []*a.Node(nil) |
| for len(p.src) > 0 { |
| if p.src[0].ID.Key() == stop { |
| if stop == t.KeyCloseParen { |
| p.src = p.src[1:] |
| } |
| return ret, nil |
| } |
| |
| elem, err := parseElem(p) |
| if err != nil { |
| return nil, err |
| } |
| ret = append(ret, elem) |
| |
| switch x := p.peek1().Key(); x { |
| case stop: |
| if stop == t.KeyCloseParen { |
| p.src = p.src[1:] |
| } |
| return ret, nil |
| case t.KeyComma: |
| p.src = p.src[1:] |
| default: |
| return nil, fmt.Errorf(`parse: expected %q, got %q at %s:%d`, |
| p.tm.ByKey(stop), p.tm.ByKey(x), p.filename, p.line()) |
| } |
| } |
| return nil, fmt.Errorf(`parse: expected %q at %s:%d`, p.tm.ByKey(stop), p.filename, p.line()) |
| } |
| |
| func (p *parser) parseFieldNode() (*a.Node, error) { |
| name, err := p.parseIdent() |
| if err != nil { |
| return nil, err |
| } |
| typ, err := p.parseTypeExpr() |
| if err != nil { |
| return nil, err |
| } |
| defaultValue := (*a.Expr)(nil) |
| if p.peek1().Key() == t.KeyEq { |
| p.src = p.src[1:] |
| defaultValue, err = p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| } |
| return a.NewField(name, typ, defaultValue).Node(), nil |
| } |
| |
| func (p *parser) parseTypeExpr() (*a.TypeExpr, error) { |
| if p.peek1().Key() == t.KeyPtr { |
| p.src = p.src[1:] |
| rhs, err := p.parseTypeExpr() |
| if err != nil { |
| return nil, err |
| } |
| return a.NewTypeExpr(t.IDPtr, 0, nil, nil, rhs), nil |
| } |
| |
| if p.peek1().Key() == t.KeyOpenBracket { |
| p.src = p.src[1:] |
| decorator, lhs := t.IDColon, (*a.Expr)(nil) |
| if p.peek1().Key() != t.KeyCloseBracket { |
| decorator = t.IDOpenBracket |
| var err error |
| lhs, err = p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| if x := p.peek1().Key(); x != t.KeyCloseBracket { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected "]", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| } |
| p.src = p.src[1:] |
| rhs, err := p.parseTypeExpr() |
| if err != nil { |
| return nil, err |
| } |
| return a.NewTypeExpr(decorator, 0, lhs, nil, rhs), nil |
| } |
| |
| pkg, name, err := p.parseQualifiedIdent() |
| if err != nil { |
| return nil, err |
| } |
| |
| lhs, mhs := (*a.Expr)(nil), (*a.Expr)(nil) |
| if p.peek1().Key() == t.KeyOpenBracket { |
| _, lhs, mhs, err = p.parseBracket(t.IDDotDot) |
| if err != nil { |
| return nil, err |
| } |
| } |
| |
| return a.NewTypeExpr(pkg, name, lhs, mhs, nil), nil |
| } |
| |
| // parseBracket parses "[i:j]", "[i:]", "[:j]" and "[:]". A double dot replaces |
| // the colon if sep is t.IDDotDot instead of t.IDColon. If sep is t.IDColon, it |
| // also parses "[x]". The returned op is sep for a range or refinement and |
| // t.IDOpenBracket for an index. |
| func (p *parser) parseBracket(sep t.ID) (op t.ID, ei *a.Expr, ej *a.Expr, err error) { |
| if x := p.peek1().Key(); x != t.KeyOpenBracket { |
| got := p.tm.ByKey(x) |
| return 0, nil, nil, fmt.Errorf(`parse: expected "[", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| |
| if p.peek1() != sep { |
| ei, err = p.parseExpr() |
| if err != nil { |
| return 0, nil, nil, err |
| } |
| } |
| |
| switch x := p.peek1().Key(); { |
| case x == sep.Key(): |
| p.src = p.src[1:] |
| |
| case x == t.KeyCloseBracket && sep.Key() == t.KeyColon: |
| p.src = p.src[1:] |
| return t.IDOpenBracket, nil, ei, nil |
| |
| default: |
| extra := `` |
| if sep.Key() == t.KeyColon { |
| extra = ` or "]"` |
| } |
| got := p.tm.ByKey(x) |
| return 0, nil, nil, fmt.Errorf(`parse: expected %q%s, got %q at %s:%d`, |
| p.tm.ByID(sep), extra, got, p.filename, p.line()) |
| } |
| |
| if p.peek1().Key() != t.KeyCloseBracket { |
| ej, err = p.parseExpr() |
| if err != nil { |
| return 0, nil, nil, err |
| } |
| } |
| |
| if x := p.peek1().Key(); x != t.KeyCloseBracket { |
| got := p.tm.ByKey(x) |
| return 0, nil, nil, fmt.Errorf(`parse: expected "]", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| |
| return sep, ei, ej, nil |
| } |
| |
| func (p *parser) parseBlock() ([]*a.Node, error) { |
| if x := p.peek1().Key(); x != t.KeyOpenCurly { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected "{", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| |
| block := []*a.Node(nil) |
| for len(p.src) > 0 { |
| if p.src[0].ID.Key() == t.KeyCloseCurly { |
| p.src = p.src[1:] |
| return block, nil |
| } |
| |
| s, err := p.parseStatement() |
| if err != nil { |
| return nil, err |
| } |
| block = append(block, s) |
| |
| if x := p.peek1().Key(); x != t.KeySemicolon { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected (implicit) ";", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| } |
| return nil, fmt.Errorf(`parse: expected "}" at %s:%d`, p.filename, p.line()) |
| } |
| |
| func (p *parser) assertsSorted(asserts []*a.Node) error { |
| seenInv, seenPost := false, false |
| for _, a := range asserts { |
| switch a.Assert().Keyword().Key() { |
| case t.KeyAssert: |
| return fmt.Errorf(`parse: assertion chain cannot contain "assert", `+ |
| `only "pre", "inv" and "post" at %s:%d`, p.filename, p.line()) |
| case t.KeyPre: |
| if seenPost || seenInv { |
| break |
| } |
| continue |
| case t.KeyInv: |
| if seenPost { |
| break |
| } |
| seenInv = true |
| continue |
| default: |
| seenPost = true |
| continue |
| } |
| return fmt.Errorf(`parse: assertion chain not in "pre", "inv", "post" order at %s:%d`, |
| p.filename, p.line()) |
| } |
| return nil |
| } |
| |
| func (p *parser) parseAssertNode() (*a.Node, error) { |
| switch x := p.peek1(); x.Key() { |
| case t.KeyAssert, t.KeyPre, t.KeyInv, t.KeyPost: |
| p.src = p.src[1:] |
| condition, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| reason, args := t.ID(0), []*a.Node(nil) |
| if p.peek1().Key() == t.KeyVia { |
| p.src = p.src[1:] |
| reason = p.peek1() |
| if !reason.IsStrLiteral() { |
| got := p.tm.ByID(reason) |
| return nil, fmt.Errorf(`parse: expected string literal, got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| args, err = p.parseList(t.KeyCloseParen, (*parser).parseArgNode) |
| if err != nil { |
| return nil, err |
| } |
| } |
| return a.NewAssert(x, condition, reason, args).Node(), nil |
| } |
| return nil, fmt.Errorf(`parse: expected "assert", "pre" or "post" at %s:%d`, p.filename, p.line()) |
| } |
| |
| func (p *parser) parseStatement() (*a.Node, error) { |
| line := uint32(0) |
| if len(p.src) > 0 { |
| line = p.src[0].Line |
| } |
| n, err := p.parseStatement1() |
| if n != nil { |
| n.Raw().SetFilenameLine(p.filename, line) |
| if n.Kind() == a.KIterate { |
| for _, o := range n.Iterate().Variables() { |
| o.Raw().SetFilenameLine(p.filename, line) |
| } |
| } |
| } |
| return n, err |
| } |
| |
| func (p *parser) parseLabel() (t.ID, error) { |
| if p.peek1().Key() == t.KeyColon { |
| p.src = p.src[1:] |
| return p.parseIdent() |
| } |
| return 0, nil |
| } |
| |
| func (p *parser) parseStatement1() (*a.Node, error) { |
| switch x := p.peek1(); x.Key() { |
| case t.KeyAssert, t.KeyPre, t.KeyPost: |
| return p.parseAssertNode() |
| |
| case t.KeyBreak, t.KeyContinue: |
| p.src = p.src[1:] |
| label, err := p.parseLabel() |
| if err != nil { |
| return nil, err |
| } |
| return a.NewJump(x, label).Node(), nil |
| |
| case t.KeyIterate: |
| p.src = p.src[1:] |
| label, err := p.parseLabel() |
| if err != nil { |
| return nil, err |
| } |
| vars, err := p.parseList(t.KeyCloseParen, (*parser).parseIterateVariableNode) |
| if err != nil { |
| return nil, err |
| } |
| body, err := p.parseBlock() |
| if err != nil { |
| return nil, err |
| } |
| return a.NewIterate(label, vars, body).Node(), nil |
| |
| case t.KeyWhile: |
| p.src = p.src[1:] |
| label, err := p.parseLabel() |
| if err != nil { |
| return nil, err |
| } |
| condition, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| asserts := []*a.Node(nil) |
| if p.peek1().Key() == t.KeyComma { |
| p.src = p.src[1:] |
| asserts, err = p.parseList(t.KeyOpenCurly, (*parser).parseAssertNode) |
| if err != nil { |
| return nil, err |
| } |
| if err := p.assertsSorted(asserts); err != nil { |
| return nil, err |
| } |
| } |
| body, err := p.parseBlock() |
| if err != nil { |
| return nil, err |
| } |
| return a.NewWhile(label, condition, asserts, body).Node(), nil |
| |
| case t.KeyIf: |
| o, err := p.parseIf() |
| return o.Node(), err |
| |
| case t.KeyReturn: |
| p.src = p.src[1:] |
| keyword, message, value, err := t.ID(0), t.ID(0), (*a.Expr)(nil), error(nil) |
| switch x := p.peek1(); x.Key() { |
| case t.KeySemicolon: |
| // No-op. |
| case t.KeyError, t.KeySuspension: |
| keyword = x |
| p.src = p.src[1:] |
| message = p.peek1() |
| if !message.IsStrLiteral() { |
| got := p.tm.ByID(message) |
| return nil, fmt.Errorf(`parse: expected string literal, got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| default: |
| value, err = p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| } |
| return a.NewReturn(keyword, message, value).Node(), nil |
| |
| case t.KeyVar: |
| p.src = p.src[1:] |
| return p.parseVar(false) |
| } |
| |
| lhs, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| |
| if op := p.peek1(); op.IsAssign() { |
| p.src = p.src[1:] |
| rhs, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| return a.NewAssign(op, lhs, rhs).Node(), nil |
| } |
| |
| return lhs.Node(), nil |
| } |
| |
| func (p *parser) parseIf() (*a.If, error) { |
| if x := p.peek1().Key(); x != t.KeyIf { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected "if", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| condition, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| bodyIfTrue, err := p.parseBlock() |
| if err != nil { |
| return nil, err |
| } |
| elseIf, bodyIfFalse := (*a.If)(nil), ([]*a.Node)(nil) |
| if p.peek1().Key() == t.KeyElse { |
| p.src = p.src[1:] |
| if p.peek1().Key() == t.KeyIf { |
| elseIf, err = p.parseIf() |
| if err != nil { |
| return nil, err |
| } |
| } else { |
| bodyIfFalse, err = p.parseBlock() |
| if err != nil { |
| return nil, err |
| } |
| } |
| } |
| return a.NewIf(condition, elseIf, bodyIfTrue, bodyIfFalse), nil |
| } |
| |
| func (p *parser) parseArgNode() (*a.Node, error) { |
| name, err := p.parseIdent() |
| if err != nil { |
| return nil, err |
| } |
| if x := p.peek1().Key(); x != t.KeyColon { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected ":", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| value, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| return a.NewArg(name, value).Node(), nil |
| } |
| |
| func (p *parser) parseIterateVariableNode() (*a.Node, error) { |
| return p.parseVar(true) |
| } |
| |
| func (p *parser) parseVar(inIterate bool) (*a.Node, error) { |
| id, err := p.parseIdent() |
| if err != nil { |
| return nil, err |
| } |
| typ, err := p.parseTypeExpr() |
| if err != nil { |
| return nil, err |
| } |
| value := (*a.Expr)(nil) |
| |
| op := t.ID(0) |
| if inIterate { |
| op = t.IDColon |
| if x := p.peek1().Key(); x != t.KeyColon { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected ":", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| value, err = p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| |
| } else if p.peek1().Key() == t.KeyEq { |
| op = t.IDEq |
| p.src = p.src[1:] |
| switch p.peek1().Key() { |
| case t.KeyLimit: |
| value, err = p.parseLimitExpr() |
| if err != nil { |
| return nil, err |
| } |
| case t.KeyTry: |
| value, err = p.parseTryExpr() |
| if err != nil { |
| return nil, err |
| } |
| default: |
| value, err = p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| } |
| } |
| |
| return a.NewVar(op, id, typ, value).Node(), nil |
| } |
| |
| func (p *parser) parseDollarExpr() (*a.Expr, error) { |
| if x := p.peek1().Key(); x != t.KeyDollar { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected "$", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| args, err := p.parseList(t.KeyCloseParen, (*parser).parseExprNode) |
| if err != nil { |
| return nil, err |
| } |
| return a.NewExpr(0, t.IDDollar, 0, nil, nil, nil, args), nil |
| } |
| |
| func (p *parser) parseLimitExpr() (*a.Expr, error) { |
| if x := p.peek1().Key(); x != t.KeyLimit { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected "limit", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| if x := p.peek1().Key(); x != t.KeyOpenParen { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected "(", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| lhs, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| if x := p.peek1().Key(); x != t.KeyCloseParen { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected ")", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| rhs, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| return a.NewExpr(0, t.IDLimit, 0, lhs.Node(), nil, rhs.Node(), nil), nil |
| } |
| |
| func (p *parser) parseTryExpr() (*a.Expr, error) { |
| if x := p.peek1().Key(); x != t.KeyTry { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected "try", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| call, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| if call.ID0() != t.IDOpenParen { |
| return nil, fmt.Errorf(`parse: expected function call after "try", got %q at %s:%d`, |
| call.String(p.tm), p.filename, p.line()) |
| } |
| return a.NewExpr(call.Node().Raw().Flags(), t.IDTry, call.ID1(), |
| call.LHS(), call.MHS(), call.RHS(), call.Args()), nil |
| } |
| |
| func (p *parser) parseExprNode() (*a.Node, error) { |
| n, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| return n.Node(), err |
| } |
| |
| func (p *parser) parseExpr() (*a.Expr, error) { |
| lhs, err := p.parseOperand() |
| if err != nil { |
| return nil, err |
| } |
| if x := p.peek1(); x.IsBinaryOp() { |
| p.src = p.src[1:] |
| rhs := (*a.Node)(nil) |
| if x.Key() == t.KeyAs { |
| o, err := p.parseTypeExpr() |
| if err != nil { |
| return nil, err |
| } |
| rhs = o.Node() |
| } else { |
| o, err := p.parseOperand() |
| if err != nil { |
| return nil, err |
| } |
| rhs = o.Node() |
| } |
| |
| if !x.IsAssociativeOp() || x != p.peek1() { |
| op := x.BinaryForm() |
| if op == 0 { |
| return nil, fmt.Errorf(`parse: internal error: no binary form for token.Key 0x%#02x`, x.Key()) |
| } |
| return a.NewExpr(0, op, 0, lhs.Node(), nil, rhs, nil), nil |
| } |
| |
| args := []*a.Node{lhs.Node(), rhs} |
| for p.peek1() == x { |
| p.src = p.src[1:] |
| arg, err := p.parseOperand() |
| if err != nil { |
| return nil, err |
| } |
| args = append(args, arg.Node()) |
| } |
| op := x.AssociativeForm() |
| if op == 0 { |
| return nil, fmt.Errorf(`parse: internal error: no associative form for token.Key 0x%#02x`, x.Key()) |
| } |
| return a.NewExpr(0, op, 0, nil, nil, nil, args), nil |
| } |
| return lhs, nil |
| } |
| |
| func (p *parser) parseOperand() (*a.Expr, error) { |
| switch x := p.peek1(); { |
| case x.Key() == t.KeyOpenParen: |
| p.src = p.src[1:] |
| expr, err := p.parseExpr() |
| if err != nil { |
| return nil, err |
| } |
| if x := p.peek1().Key(); x != t.KeyCloseParen { |
| got := p.tm.ByKey(x) |
| return nil, fmt.Errorf(`parse: expected ")", got %q at %s:%d`, got, p.filename, p.line()) |
| } |
| p.src = p.src[1:] |
| return expr, nil |
| |
| case x.IsUnaryOp(): |
| p.src = p.src[1:] |
| rhs, err := p.parseOperand() |
| if err != nil { |
| return nil, err |
| } |
| op := x.UnaryForm() |
| if op == 0 { |
| return nil, fmt.Errorf(`parse: internal error: no unary form for token.Key 0x%#02x`, x.Key()) |
| } |
| return a.NewExpr(0, op, 0, nil, nil, rhs.Node(), nil), nil |
| |
| case x.IsLiteral(): |
| p.src = p.src[1:] |
| return a.NewExpr(0, 0, x, nil, nil, nil, nil), nil |
| } |
| |
| id, err := p.parseIdent() |
| if err != nil { |
| return nil, err |
| } |
| lhs := a.NewExpr(0, 0, id, nil, nil, nil, nil) |
| |
| for { |
| flags := a.Flags(0) |
| switch p.peek1().Key() { |
| default: |
| return lhs, nil |
| |
| case t.KeyExclam, t.KeyQuestion: |
| flags |= a.FlagsImpure | a.FlagsCallImpure |
| if p.src[0].Key() == t.KeyQuestion { |
| flags |= a.FlagsSuspendible | a.FlagsCallSuspendible |
| } |
| p.src = p.src[1:] |
| fallthrough |
| |
| case t.KeyOpenParen: |
| args, err := p.parseList(t.KeyCloseParen, (*parser).parseArgNode) |
| if err != nil { |
| return nil, err |
| } |
| lhs = a.NewExpr(flags, t.IDOpenParen, 0, lhs.Node(), nil, nil, args) |
| |
| case t.KeyOpenBracket: |
| id0, mhs, rhs, err := p.parseBracket(t.IDColon) |
| if err != nil { |
| return nil, err |
| } |
| lhs = a.NewExpr(0, id0, 0, lhs.Node(), mhs.Node(), rhs.Node(), nil) |
| |
| case t.KeyDot: |
| p.src = p.src[1:] |
| selector, err := p.parseIdent() |
| if err != nil { |
| return nil, err |
| } |
| lhs = a.NewExpr(0, t.IDDot, selector, lhs.Node(), nil, nil, nil) |
| } |
| } |
| } |
