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woodpecker/vendor/github.com/eknkc/amber/parser/scanner.go
2015-09-29 18:21:17 -07:00

502 lines
10 KiB
Go

package parser
import (
"bufio"
"container/list"
"fmt"
"io"
"regexp"
)
const (
tokEOF = -(iota + 1)
tokDoctype
tokComment
tokIndent
tokOutdent
tokBlank
tokId
tokClassName
tokTag
tokText
tokAttribute
tokIf
tokElse
tokEach
tokAssignment
tokImport
tokNamedBlock
tokExtends
tokMixin
tokMixinCall
)
const (
scnNewLine = iota
scnLine
scnEOF
)
type scanner struct {
reader *bufio.Reader
indentStack *list.List
stash *list.List
state int32
buffer string
line int
col int
lastTokenLine int
lastTokenCol int
lastTokenSize int
readRaw bool
}
type token struct {
Kind rune
Value string
Data map[string]string
}
func newScanner(r io.Reader) *scanner {
s := new(scanner)
s.reader = bufio.NewReader(r)
s.indentStack = list.New()
s.stash = list.New()
s.state = scnNewLine
s.line = -1
s.col = 0
return s
}
func (s *scanner) Pos() SourcePosition {
return SourcePosition{s.lastTokenLine + 1, s.lastTokenCol + 1, s.lastTokenSize, ""}
}
// Returns next token found in buffer
func (s *scanner) Next() *token {
if s.readRaw {
s.readRaw = false
return s.NextRaw()
}
s.ensureBuffer()
if stashed := s.stash.Front(); stashed != nil {
tok := stashed.Value.(*token)
s.stash.Remove(stashed)
return tok
}
switch s.state {
case scnEOF:
if outdent := s.indentStack.Back(); outdent != nil {
s.indentStack.Remove(outdent)
return &token{tokOutdent, "", nil}
}
return &token{tokEOF, "", nil}
case scnNewLine:
s.state = scnLine
if tok := s.scanIndent(); tok != nil {
return tok
}
return s.Next()
case scnLine:
if tok := s.scanMixin(); tok != nil {
return tok
}
if tok := s.scanMixinCall(); tok != nil {
return tok
}
if tok := s.scanDoctype(); tok != nil {
return tok
}
if tok := s.scanCondition(); tok != nil {
return tok
}
if tok := s.scanEach(); tok != nil {
return tok
}
if tok := s.scanImport(); tok != nil {
return tok
}
if tok := s.scanExtends(); tok != nil {
return tok
}
if tok := s.scanBlock(); tok != nil {
return tok
}
if tok := s.scanAssignment(); tok != nil {
return tok
}
if tok := s.scanTag(); tok != nil {
return tok
}
if tok := s.scanId(); tok != nil {
return tok
}
if tok := s.scanClassName(); tok != nil {
return tok
}
if tok := s.scanAttribute(); tok != nil {
return tok
}
if tok := s.scanComment(); tok != nil {
return tok
}
if tok := s.scanText(); tok != nil {
return tok
}
}
return nil
}
func (s *scanner) NextRaw() *token {
result := ""
level := 0
for {
s.ensureBuffer()
switch s.state {
case scnEOF:
return &token{tokText, result, map[string]string{"Mode": "raw"}}
case scnNewLine:
s.state = scnLine
if tok := s.scanIndent(); tok != nil {
if tok.Kind == tokIndent {
level++
} else if tok.Kind == tokOutdent {
level--
} else {
result = result + "\n"
continue
}
if level < 0 {
s.stash.PushBack(&token{tokOutdent, "", nil})
if len(result) > 0 && result[len(result)-1] == '\n' {
result = result[:len(result)-1]
}
return &token{tokText, result, map[string]string{"Mode": "raw"}}
}
}
case scnLine:
if len(result) > 0 {
result = result + "\n"
}
for i := 0; i < level; i++ {
result += "\t"
}
result = result + s.buffer
s.consume(len(s.buffer))
}
}
return nil
}
var rgxIndent = regexp.MustCompile(`^(\s+)`)
func (s *scanner) scanIndent() *token {
if len(s.buffer) == 0 {
return &token{tokBlank, "", nil}
}
var head *list.Element
for head = s.indentStack.Front(); head != nil; head = head.Next() {
value := head.Value.(*regexp.Regexp)
if match := value.FindString(s.buffer); len(match) != 0 {
s.consume(len(match))
} else {
break
}
}
newIndent := rgxIndent.FindString(s.buffer)
if len(newIndent) != 0 && head == nil {
s.indentStack.PushBack(regexp.MustCompile(regexp.QuoteMeta(newIndent)))
s.consume(len(newIndent))
return &token{tokIndent, newIndent, nil}
}
if len(newIndent) == 0 && head != nil {
for head != nil {
next := head.Next()
s.indentStack.Remove(head)
if next == nil {
return &token{tokOutdent, "", nil}
} else {
s.stash.PushBack(&token{tokOutdent, "", nil})
}
head = next
}
}
if len(newIndent) != 0 && head != nil {
panic("Mismatching indentation. Please use a coherent indent schema.")
}
return nil
}
var rgxDoctype = regexp.MustCompile(`^(!!!|doctype)\s*(.*)`)
func (s *scanner) scanDoctype() *token {
if sm := rgxDoctype.FindStringSubmatch(s.buffer); len(sm) != 0 {
if len(sm[2]) == 0 {
sm[2] = "html"
}
s.consume(len(sm[0]))
return &token{tokDoctype, sm[2], nil}
}
return nil
}
var rgxIf = regexp.MustCompile(`^if\s+(.+)$`)
var rgxElse = regexp.MustCompile(`^else\s*`)
func (s *scanner) scanCondition() *token {
if sm := rgxIf.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokIf, sm[1], nil}
}
if sm := rgxElse.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokElse, "", nil}
}
return nil
}
var rgxEach = regexp.MustCompile(`^each\s+(\$[\w0-9\-_]*)(?:\s*,\s*(\$[\w0-9\-_]*))?\s+in\s+(.+)$`)
func (s *scanner) scanEach() *token {
if sm := rgxEach.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokEach, sm[3], map[string]string{"X": sm[1], "Y": sm[2]}}
}
return nil
}
var rgxAssignment = regexp.MustCompile(`^(\$[\w0-9\-_]*)?\s*=\s*(.+)$`)
func (s *scanner) scanAssignment() *token {
if sm := rgxAssignment.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokAssignment, sm[2], map[string]string{"X": sm[1]}}
}
return nil
}
var rgxComment = regexp.MustCompile(`^\/\/(-)?\s*(.*)$`)
func (s *scanner) scanComment() *token {
if sm := rgxComment.FindStringSubmatch(s.buffer); len(sm) != 0 {
mode := "embed"
if len(sm[1]) != 0 {
mode = "silent"
}
s.consume(len(sm[0]))
return &token{tokComment, sm[2], map[string]string{"Mode": mode}}
}
return nil
}
var rgxId = regexp.MustCompile(`^#([\w-]+)(?:\s*\?\s*(.*)$)?`)
func (s *scanner) scanId() *token {
if sm := rgxId.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokId, sm[1], map[string]string{"Condition": sm[2]}}
}
return nil
}
var rgxClassName = regexp.MustCompile(`^\.([\w-]+)(?:\s*\?\s*(.*)$)?`)
func (s *scanner) scanClassName() *token {
if sm := rgxClassName.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokClassName, sm[1], map[string]string{"Condition": sm[2]}}
}
return nil
}
var rgxAttribute = regexp.MustCompile(`^\[([\w\-]+)\s*(?:=\s*(\"([^\"\\]*)\"|([^\]]+)))?\](?:\s*\?\s*(.*)$)?`)
func (s *scanner) scanAttribute() *token {
if sm := rgxAttribute.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
if len(sm[3]) != 0 || sm[2] == "" {
return &token{tokAttribute, sm[1], map[string]string{"Content": sm[3], "Mode": "raw", "Condition": sm[5]}}
}
return &token{tokAttribute, sm[1], map[string]string{"Content": sm[4], "Mode": "expression", "Condition": sm[5]}}
}
return nil
}
var rgxImport = regexp.MustCompile(`^import\s+([0-9a-zA-Z_\-\. \/]*)$`)
func (s *scanner) scanImport() *token {
if sm := rgxImport.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokImport, sm[1], nil}
}
return nil
}
var rgxExtends = regexp.MustCompile(`^extends\s+([0-9a-zA-Z_\-\. \/]*)$`)
func (s *scanner) scanExtends() *token {
if sm := rgxExtends.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokExtends, sm[1], nil}
}
return nil
}
var rgxBlock = regexp.MustCompile(`^block\s+(?:(append|prepend)\s+)?([0-9a-zA-Z_\-\. \/]*)$`)
func (s *scanner) scanBlock() *token {
if sm := rgxBlock.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokNamedBlock, sm[2], map[string]string{"Modifier": sm[1]}}
}
return nil
}
var rgxTag = regexp.MustCompile(`^(\w[-:\w]*)`)
func (s *scanner) scanTag() *token {
if sm := rgxTag.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokTag, sm[1], nil}
}
return nil
}
var rgxMixin = regexp.MustCompile(`^mixin ([a-zA-Z_]+\w*)(\(((\$\w*(,\s)?)*)\))?$`)
func (s *scanner) scanMixin() *token {
if sm := rgxMixin.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokMixin, sm[1], map[string]string{"Args": sm[3]}}
}
return nil
}
var rgxMixinCall = regexp.MustCompile(`^\+([A-Za-z_]+\w*)(\((.+(,\s)?)*\))?$`)
func (s *scanner) scanMixinCall() *token {
if sm := rgxMixinCall.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
return &token{tokMixinCall, sm[1], map[string]string{"Args": sm[3]}}
}
return nil
}
var rgxText = regexp.MustCompile(`^(\|)? ?(.*)$`)
func (s *scanner) scanText() *token {
if sm := rgxText.FindStringSubmatch(s.buffer); len(sm) != 0 {
s.consume(len(sm[0]))
mode := "inline"
if sm[1] == "|" {
mode = "piped"
}
return &token{tokText, sm[2], map[string]string{"Mode": mode}}
}
return nil
}
// Moves position forward, and removes beginning of s.buffer (len bytes)
func (s *scanner) consume(runes int) {
if len(s.buffer) < runes {
panic(fmt.Sprintf("Unable to consume %d runes from buffer.", runes))
}
s.lastTokenLine = s.line
s.lastTokenCol = s.col
s.lastTokenSize = runes
s.buffer = s.buffer[runes:]
s.col += runes
}
// Reads string into s.buffer
func (s *scanner) ensureBuffer() {
if len(s.buffer) > 0 {
return
}
buf, err := s.reader.ReadString('\n')
if err != nil && err != io.EOF {
panic(err)
} else if err != nil && len(buf) == 0 {
s.state = scnEOF
} else {
// endline "LF only" or "\n" use Unix, Linux, modern MacOS X, FreeBSD, BeOS, RISC OS
if buf[len(buf)-1] == '\n' {
buf = buf[:len(buf)-1]
}
// endline "CR+LF" or "\r\n" use internet protocols, DEC RT-11, Windows, CP/M, MS-DOS, OS/2, Symbian OS
if len(buf) > 0 && buf[len(buf)-1] == '\r' {
buf = buf[:len(buf)-1]
}
s.state = scnNewLine
s.buffer = buf
s.line += 1
s.col = 0
}
}