Commit fa497796 authored by Robert Griesemer's avatar Robert Griesemer

go/parser: report illegal label declarations at ':' rather than guessing the start

Also:
- Add parser.SpuriousError flag. If set, the parser reports all (including
  spurious) errors rather then at most one error per line.
- Add -e flag to gofmt and gotype: If set, gofmt and gotype report all
  (including spurious) errors rather than at most one error per line.
- Updated the respective documentation.

Fixes #2088.

R=rsc
CC=golang-dev
https://golang.org/cl/4803047
parent 3d552700
......@@ -14,11 +14,12 @@ Usage:
gofmt [flags] [path ...]
The flags are:
-d
Do not print reformatted sources to standard output.
If a file's formatting is different than gofmt's, print diffs
to standard output.
-e
Print all (including spurious) errors.
-l
Do not print reformatted sources to standard output.
If a file's formatting is different from gofmt's, print its name
......@@ -31,6 +32,8 @@ The flags are:
Do not print reformatted sources to standard output.
If a file's formatting is different from gofmt's, overwrite it
with gofmt's version.
Formatting control flags:
-comments=true
Print comments; if false, all comments are elided from the output.
-spaces
......@@ -40,6 +43,7 @@ The flags are:
-tabwidth=8
Tab width in spaces.
The rewrite rule specified with the -r flag must be a string of the form:
pattern -> replacement
......
......@@ -29,6 +29,7 @@ var (
rewriteRule = flag.String("r", "", "rewrite rule (e.g., 'α[β:len(α)] -> α[β:]')")
simplifyAST = flag.Bool("s", false, "simplify code")
doDiff = flag.Bool("d", false, "display diffs instead of rewriting files")
allErrors = flag.Bool("e", false, "print all (including spurious) errors")
// layout control
comments = flag.Bool("comments", true, "print comments")
......@@ -64,6 +65,9 @@ func initParserMode() {
if *comments {
parserMode |= parser.ParseComments
}
if *allErrors {
parserMode |= parser.SpuriousErrors
}
}
func initPrinterMode() {
......
......@@ -24,18 +24,20 @@ Usage:
gotype [flags] [path ...]
The flags are:
-e
Print all (including spurious) errors.
-p pkgName
process only those files in package pkgName.
Process only those files in package pkgName.
-r
recursively process subdirectories.
Recursively process subdirectories.
-v
verbose mode.
Verbose mode.
Debugging flags:
-trace
print parse trace (disables concurrent parsing).
-ast
print AST (disables concurrent parsing).
Print AST (disables concurrent parsing).
-trace
Print parse trace (disables concurrent parsing).
Examples
......
......@@ -23,6 +23,7 @@ var (
pkgName = flag.String("p", "", "process only those files in package pkgName")
recursive = flag.Bool("r", false, "recursively process subdirectories")
verbose = flag.Bool("v", false, "verbose mode")
allErrors = flag.Bool("e", false, "print all (including spurious) errors")
// debugging support
printTrace = flag.Bool("trace", false, "print parse trace")
......@@ -68,6 +69,9 @@ func parse(fset *token.FileSet, filename string, src []byte) *ast.File {
// parse entire file
mode := parser.DeclarationErrors
if *allErrors {
mode |= parser.SpuriousErrors
}
if *printTrace {
mode |= parser.Trace
}
......
......@@ -48,9 +48,12 @@ func readSource(filename string, src interface{}) ([]byte, os.Error) {
return ioutil.ReadFile(filename)
}
func (p *parser) parseEOF() os.Error {
p.expect(token.EOF)
return p.GetError(scanner.Sorted)
func (p *parser) errors() os.Error {
mode := scanner.Sorted
if p.mode&SpuriousErrors == 0 {
mode = scanner.NoMultiples
}
return p.GetError(mode)
}
// ParseExpr parses a Go expression and returns the corresponding
......@@ -70,7 +73,9 @@ func ParseExpr(fset *token.FileSet, filename string, src interface{}) (ast.Expr,
if p.tok == token.SEMICOLON {
p.next() // consume automatically inserted semicolon, if any
}
return x, p.parseEOF()
p.expect(token.EOF)
return x, p.errors()
}
// ParseStmtList parses a list of Go statements and returns the list
......@@ -86,7 +91,10 @@ func ParseStmtList(fset *token.FileSet, filename string, src interface{}) ([]ast
var p parser
p.init(fset, filename, data, 0)
return p.parseStmtList(), p.parseEOF()
list := p.parseStmtList()
p.expect(token.EOF)
return list, p.errors()
}
// ParseDeclList parses a list of Go declarations and returns the list
......@@ -102,7 +110,10 @@ func ParseDeclList(fset *token.FileSet, filename string, src interface{}) ([]ast
var p parser
p.init(fset, filename, data, 0)
return p.parseDeclList(), p.parseEOF()
list := p.parseDeclList()
p.expect(token.EOF)
return list, p.errors()
}
// ParseFile parses the source code of a single Go source file and returns
......@@ -133,7 +144,9 @@ func ParseFile(fset *token.FileSet, filename string, src interface{}, mode uint)
var p parser
p.init(fset, filename, data, mode)
return p.parseFile(), p.GetError(scanner.NoMultiples) // parseFile() reads to EOF
file := p.parseFile() // parseFile reads to EOF
return file, p.errors()
}
// ParseFiles calls ParseFile for each file in the filenames list and returns
......
......@@ -26,6 +26,7 @@ const (
ParseComments // parse comments and add them to AST
Trace // print a trace of parsed productions
DeclarationErrors // report declaration errors
SpuriousErrors // report all (not just the first) errors per line
)
// The parser structure holds the parser's internal state.
......@@ -1408,7 +1409,13 @@ func (p *parser) parseSimpleStmt(labelOk bool) ast.Stmt {
p.declare(stmt, nil, p.labelScope, ast.Lbl, label)
return stmt
}
p.error(x[0].Pos(), "illegal label declaration")
// The label declaration typically starts at x[0].Pos(), but the label
// declaration may be erroneous due to a token after that position (and
// before the ':'). If SpuriousErrors is not set, the (only) error re-
// ported for the line is the illegal label error instead of the token
// before the ':' that caused the problem. Thus, use the (latest) colon
// position for error reporting.
p.error(colon, "illegal label declaration")
return &ast.BadStmt{x[0].Pos(), colon + 1}
case token.ARROW:
......
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