diff options
Diffstat (limited to 'src/pkg/exp/template/lex.go')
-rw-r--r-- | src/pkg/exp/template/lex.go | 88 |
1 files changed, 58 insertions, 30 deletions
diff --git a/src/pkg/exp/template/lex.go b/src/pkg/exp/template/lex.go index 1919cf4715..d22d825a1d 100644 --- a/src/pkg/exp/template/lex.go +++ b/src/pkg/exp/template/lex.go @@ -18,60 +18,71 @@ type item struct { } func (i item) String() string { - switch i.typ { - case itemEOF: + switch { + case i.typ == itemEOF: return "EOF" - case itemError: + case i.typ == itemError: return i.val - } - if len(i.val) > 10 { + case i.typ > itemKeyword: + return fmt.Sprintf("<%s>", i.val) + case len(i.val) > 10: return fmt.Sprintf("%.10q...", i.val) } return fmt.Sprintf("%q", i.val) } -// itemType identifies the type of lex item. +// itemType identifies the type of lex items. type itemType int const ( - itemError itemType = iota // error occurred; value is text of error - itemBool // boolean constant - itemDot // the cursor, spelled '.'. + itemError itemType = iota // error occurred; value is text of error + itemBool // boolean constant + itemComplex // complex constant (1+2i); imaginary is just a number itemEOF - itemElse // else keyword - itemEnd // end keyword itemField // alphanumeric identifier, starting with '.', possibly chained ('.x.y') itemIdentifier // alphanumeric identifier - itemIf // if keyword itemLeftMeta // left meta-string - itemNumber // number + itemNumber // simple number, including imaginary itemPipe // pipe symbol - itemRange // range keyword itemRawString // raw quoted string (includes quotes) itemRightMeta // right meta-string itemString // quoted string (includes quotes) itemText // plain text + // Keywords appear after all the rest. + itemKeyword // used only to delimit the keywords + itemDot // the cursor, spelled '.'. + itemDefine // define keyword + itemElse // else keyword + itemEnd // end keyword + itemIf // if keyword + itemRange // range keyword + itemTemplate // template keyword + itemWith // with keyword ) // Make the types prettyprint. var itemName = map[itemType]string{ itemError: "error", itemBool: "bool", - itemDot: ".", + itemComplex: "complex", itemEOF: "EOF", - itemElse: "else", - itemEnd: "end", itemField: "field", itemIdentifier: "identifier", - itemIf: "if", itemLeftMeta: "left meta", itemNumber: "number", itemPipe: "pipe", - itemRange: "range", itemRawString: "raw string", itemRightMeta: "rightMeta", itemString: "string", - itemText: "text", + // keywords + itemDot: ".", + itemDefine: "define", + itemElse: "else", + itemIf: "if", + itemEnd: "end", + itemRange: "range", + itemTemplate: "template", + itemWith: "with", } func (i itemType) String() string { @@ -83,11 +94,14 @@ func (i itemType) String() string { } var key = map[string]itemType{ - ".": itemDot, - "else": itemElse, - "end": itemEnd, - "if": itemIf, - "range": itemRange, + ".": itemDot, + "define": itemDefine, + "else": itemElse, + "end": itemEnd, + "if": itemIf, + "range": itemRange, + "template": itemTemplate, + "with": itemWith, } const eof = -1 @@ -282,7 +296,7 @@ Loop: l.backup() word := l.input[l.start:l.pos] switch { - case key[word] != itemError: + case key[word] > itemKeyword: l.emit(key[word]) case word[0] == '.': l.emit(itemField) @@ -301,8 +315,23 @@ Loop: // isn't a perfect number scanner - for instance it accepts "." and "0x0.2" // and "089" - but when it's wrong the input is invalid and the parser (via // strconv) will notice. -// TODO: without expressions you can do imaginary but not complex. func lexNumber(l *lexer) stateFn { + if !l.scanNumber() { + return l.errorf("bad number syntax: %q", l.input[l.start:l.pos]) + } + if sign := l.peek(); sign == '+' || sign == '-' { + // Complex: 1+2i. No spaces, must end in 'i'. + if !l.scanNumber() || l.input[l.pos-1] != 'i' { + return l.errorf("bad number syntax: %q", l.input[l.start:l.pos]) + } + l.emit(itemComplex) + } else { + l.emit(itemNumber) + } + return lexInsideAction +} + +func (l *lexer) scanNumber() bool { // Optional leading sign. l.accept("+-") // Is it hex? @@ -323,10 +352,9 @@ func lexNumber(l *lexer) stateFn { // Next thing mustn't be alphanumeric. if isAlphaNumeric(l.peek()) { l.next() - return l.errorf("bad number syntax: %q", l.input[l.start:l.pos]) + return false } - l.emit(itemNumber) - return lexInsideAction + return true } // lexQuote scans a quoted string. |