diff options
Diffstat (limited to 'src/cmd')
| -rw-r--r-- | src/cmd/compile/fmt_test.go | 3 | ||||
| -rw-r--r-- | src/cmd/compile/internal/syntax/parser.go | 62 |
2 files changed, 42 insertions, 23 deletions
diff --git a/src/cmd/compile/fmt_test.go b/src/cmd/compile/fmt_test.go index 17716f82f2..e4707fb310 100644 --- a/src/cmd/compile/fmt_test.go +++ b/src/cmd/compile/fmt_test.go @@ -614,6 +614,7 @@ var knownFormats = map[string]string{ "[]cmd/compile/internal/ssa.Edge %v": "", "[]cmd/compile/internal/ssa.ID %v": "", "[]cmd/compile/internal/ssa.VarLocList %v": "", + "[]cmd/compile/internal/syntax.token %s": "", "[]string %v": "", "bool %v": "", "byte %08b": "", @@ -683,9 +684,9 @@ var knownFormats = map[string]string{ "int32 %d": "", "int32 %v": "", "int32 %x": "", - "int64 %.5d": "", "int64 %+d": "", "int64 %-10d": "", + "int64 %.5d": "", "int64 %X": "", "int64 %d": "", "int64 %v": "", diff --git a/src/cmd/compile/internal/syntax/parser.go b/src/cmd/compile/internal/syntax/parser.go index b77356a7e5..b967279089 100644 --- a/src/cmd/compile/internal/syntax/parser.go +++ b/src/cmd/compile/internal/syntax/parser.go @@ -97,7 +97,7 @@ func (p *parser) got(tok token) bool { func (p *parser) want(tok token) { if !p.got(tok) { - p.syntax_error("expecting " + tok.String()) + p.syntax_error("expecting " + tokstring(tok)) p.advance() } } @@ -126,7 +126,7 @@ func (p *parser) error_at(pos src.Pos, msg string) { // syntax_error_at reports a syntax error at the given position. func (p *parser) syntax_error_at(pos src.Pos, msg string) { if trace { - defer p.trace("syntax_error (" + msg + ")")() + p.print("syntax error: " + msg) } if p.tok == _EOF && p.first != nil { @@ -168,6 +168,18 @@ func (p *parser) syntax_error_at(pos src.Pos, msg string) { p.error_at(pos, "syntax error: unexpected "+tok+msg) } +// tokstring returns the English word for selected punctuation tokens +// for more readable error messages. +func tokstring(tok token) string { + switch tok { + case _Comma: + return "comma" + case _Semi: + return "semicolon" + } + return tok.String() +} + // Convenience methods using the current token position. func (p *parser) pos() src.Pos { return p.pos_at(p.line, p.col) } func (p *parser) error(msg string) { p.error_at(p.pos(), msg) } @@ -194,40 +206,42 @@ const stopset uint64 = 1<<_Break | // Advance consumes tokens until it finds a token of the stopset or followlist. // The stopset is only considered if we are inside a function (p.fnest > 0). // The followlist is the list of valid tokens that can follow a production; -// if it is empty, exactly one token is consumed to ensure progress. +// if it is empty, exactly one (non-EOF) token is consumed to ensure progress. func (p *parser) advance(followlist ...token) { - if len(followlist) == 0 { - p.next() - return + if trace { + p.print(fmt.Sprintf("advance %s", followlist)) } // compute follow set // (not speed critical, advance is only called in error situations) - var followset uint64 = 1 << _EOF // never skip over EOF - for _, tok := range followlist { - followset |= 1 << tok + var followset uint64 = 1 << _EOF // don't skip over EOF + if len(followlist) > 0 { + if p.fnest > 0 { + followset |= stopset + } + for _, tok := range followlist { + followset |= 1 << tok + } } - for !(contains(followset, p.tok) || p.fnest > 0 && contains(stopset, p.tok)) { + for !contains(followset, p.tok) { + if trace { + p.print("skip " + p.tok.String()) + } p.next() + if len(followlist) == 0 { + break + } } -} -func tokstring(tok token) string { - switch tok { - case _EOF: - return "EOF" - case _Comma: - return "comma" - case _Semi: - return "semicolon" + if trace { + p.print("next " + p.tok.String()) } - return tok.String() } // usage: defer p.trace(msg)() func (p *parser) trace(msg string) func() { - fmt.Printf("%5d: %s%s (\n", p.line, p.indent, msg) + p.print(msg + " (") const tab = ". " p.indent = append(p.indent, tab...) return func() { @@ -235,10 +249,14 @@ func (p *parser) trace(msg string) func() { if x := recover(); x != nil { panic(x) // skip print_trace } - fmt.Printf("%5d: %s)\n", p.line, p.indent) + p.print(")") } } +func (p *parser) print(msg string) { + fmt.Printf("%5d: %s%s\n", p.line, p.indent, msg) +} + // ---------------------------------------------------------------------------- // Package files // |