From 7717384414926eaa5821f04a08ee0d198f7b786f Mon Sep 17 00:00:00 2001 From: Mel Date: Mon, 8 Aug 2022 23:46:09 +0000 Subject: Produce (slightly) better parser errors --- pkg/lang/parser/errors.go | 60 ++++++++++++++++++++++++++++++++++ pkg/lang/parser/exprs.go | 8 ++--- pkg/lang/parser/parser.go | 7 ++-- pkg/lang/parser/stmts.go | 8 +++-- pkg/lang/scanner/token/token.go | 72 ++++++++++++++++++++++++++++++++++++++++- pkg/libs/source/loc.go | 6 ++++ 6 files changed, 151 insertions(+), 10 deletions(-) create mode 100644 pkg/lang/parser/errors.go (limited to 'pkg') diff --git a/pkg/lang/parser/errors.go b/pkg/lang/parser/errors.go new file mode 100644 index 0000000..a020e01 --- /dev/null +++ b/pkg/lang/parser/errors.go @@ -0,0 +1,60 @@ +package parser + +import ( + "fmt" + "jinx/pkg/lang/scanner/token" + "jinx/pkg/libs/source" +) + +type ErrFunctionNoThisAllowed struct { + At source.Loc +} + +func (e ErrFunctionNoThisAllowed) Error() string { + return fmt.Sprintf("non-method function cannot have 'this' as parameter at %v", e.At) +} + +type ErrFunctionLiteralNoThisAllowed struct { + At source.Loc +} + +func (e ErrFunctionLiteralNoThisAllowed) Error() string { + return fmt.Sprintf("function literal cannot have 'this' as parameter at %v", e.At) +} + +type ErrExpectedToken struct { + At source.Loc + Wanted token.TokenKind + Got token.Token +} + +func (e ErrExpectedToken) Error() string { + return fmt.Sprintf("unexpected token %v, wanted %v at %v", e.Got, e.Wanted, e.At) +} + +type ErrExpectedStatementEnd struct { + At source.Loc + Got token.Token +} + +func (e ErrExpectedStatementEnd) Error() string { + return fmt.Sprintf("expected statement end, got %v at %v", e.Got, e.At) +} + +type ErrExpectedUnitExpressionStart struct { + At source.Loc + Got token.Token +} + +func (e ErrExpectedUnitExpressionStart) Error() string { + return fmt.Sprintf("unexpected token %v, wanted unit expression start at %v", e.Got, e.At) +} + +type ErrExpectedValueLiteral struct { + At source.Loc + Got token.Token +} + +func (e ErrExpectedValueLiteral) Error() string { + return fmt.Sprintf("unexpected token %v, wanted value literal %v", e.Got, e.At) +} diff --git a/pkg/lang/parser/exprs.go b/pkg/lang/parser/exprs.go index 48d1a8c..1603838 100644 --- a/pkg/lang/parser/exprs.go +++ b/pkg/lang/parser/exprs.go @@ -1,7 +1,6 @@ package parser import ( - "fmt" "jinx/pkg/lang/ast" "jinx/pkg/lang/scanner/token" ) @@ -207,7 +206,8 @@ func (p *Parser) parseUnitExpr() (ast.Expr, error) { case token.KwTrue, token.KwFalse, token.KwNull, token.KwThis: return p.parseValueLitExpr() default: - panic(fmt.Errorf("unexpected token '%v', wanted unit expression start", p.peek().Kind)) + tok := p.peek() + return ast.Expr{}, ErrExpectedUnitExpressionStart{tok.At, tok} } } @@ -250,7 +250,7 @@ func (p *Parser) parseFnLitExpr() (ast.Expr, error) { } if hasThis { - return ast.Expr{}, fmt.Errorf("function literal cannot have 'this' parameter") + return ast.Expr{}, ErrFunctionLiteralNoThisAllowed{fnTok.At} } // TODO: Also parse just an expression @@ -406,6 +406,6 @@ func (p *Parser) parseValueLitExpr() (ast.Expr, error) { Value: ast.ExprThis{}, }, nil default: - panic(fmt.Errorf("unexpected token '%v', wanted value literal", tok)) + return ast.Expr{}, ErrExpectedValueLiteral{At: tok.At, Got: tok} } } diff --git a/pkg/lang/parser/parser.go b/pkg/lang/parser/parser.go index 0ff4b09..d939e4b 100644 --- a/pkg/lang/parser/parser.go +++ b/pkg/lang/parser/parser.go @@ -1,7 +1,6 @@ package parser import ( - "fmt" "jinx/pkg/lang/ast" "jinx/pkg/lang/scanner/token" ) @@ -88,7 +87,11 @@ func (p *Parser) next() token.Token { func (p *Parser) expect(kind token.TokenKind) (token.Token, error) { tok := p.next() if tok.Kind != kind { - return token.Token{}, fmt.Errorf("expected '%v', got '%v'", kind, tok.Kind) + return token.Token{}, ErrExpectedToken{ + At: tok.At, + Wanted: kind, + Got: tok, + } } return tok, nil diff --git a/pkg/lang/parser/stmts.go b/pkg/lang/parser/stmts.go index c20f7a0..fe5c65b 100644 --- a/pkg/lang/parser/stmts.go +++ b/pkg/lang/parser/stmts.go @@ -1,7 +1,6 @@ package parser import ( - "fmt" "jinx/pkg/lang/ast" "jinx/pkg/lang/scanner/token" ) @@ -154,7 +153,7 @@ func (p *Parser) parseFnDeclStmt() (ast.Stmt, error) { } if hasThis { - return ast.Stmt{}, fmt.Errorf("function cannot have 'this' as a parameter") + return ast.Stmt{}, ErrFunctionNoThisAllowed{At: fnTok.At} } block, err := p.parseBlock() @@ -640,7 +639,10 @@ func (p *Parser) parseEmptyStmt() (ast.Stmt, error) { func (p *Parser) parseStmtEnd() error { tok := p.peek() if !tok.CanEndStmt() { - return fmt.Errorf("wanted statement end, received: '%v'", tok.Kind) + return ErrExpectedStatementEnd{ + At: tok.At, + Got: tok, + } } p.next() return nil diff --git a/pkg/lang/scanner/token/token.go b/pkg/lang/scanner/token/token.go index a39df8a..9fee730 100644 --- a/pkg/lang/scanner/token/token.go +++ b/pkg/lang/scanner/token/token.go @@ -1,6 +1,9 @@ package token -import "jinx/pkg/libs/source" +import ( + "fmt" + "jinx/pkg/libs/source" +) type Token struct { Kind TokenKind @@ -31,3 +34,70 @@ func (t Token) CanEndStmt() bool { return false } } + +func (t Token) String() string { + switch t.Kind { + case EOF, EOL: + return t.Kind.String() + + case KwVar, + KwFn, + KwType, + KwIf, + KwElif, + KwElse, + KwFor, + KwTry, + KwCatch, + KwFinally, + KwReturn, + KwContinue, + KwBreak, + KwThrow, + KwIn, + KwNull, + KwTrue, + KwFalse, + KwThis, + KwUse, + KwFrom, + KwBy, + KwGlobal: + return fmt.Sprintf("keyword '%v'", t.Kind) + + case Ident: + return fmt.Sprintf("identifier '%v'", t.Data) + case Int: + return fmt.Sprintf("integer '%v'", t.Data) + case Float: + return fmt.Sprintf("float '%v'", t.Data) + case String: + return fmt.Sprintf("string '%v'", t.Data) + + case Assign, + Plus, + Minus, + Star, + Slash, + Percent, + Bang, + Eq, + Neq, + Lt, + Gt, + Lte, + Gte, + LParen, + RParen, + LBrace, + RBrace, + LBracket, + RBracket, + Comma, + Dot, + SemiColon: + return fmt.Sprintf("'%v'", t.Kind) + default: + return "unknown token" + } +} diff --git a/pkg/libs/source/loc.go b/pkg/libs/source/loc.go index 3089d3b..f43b5c0 100644 --- a/pkg/libs/source/loc.go +++ b/pkg/libs/source/loc.go @@ -1,5 +1,7 @@ package source +import "fmt" + type Loc struct { Row int Col int @@ -8,3 +10,7 @@ type Loc struct { func NewLoc(row, col int) Loc { return Loc{row, col} } + +func (l Loc) String() string { + return fmt.Sprintf("%d:%d", l.Row+1, l.Col) +} -- cgit 1.4.1