377 lines
8.3 KiB
Go
377 lines
8.3 KiB
Go
package lexer
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import "io"
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import "fmt"
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import "github.com/sashakoshka/arf/file"
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import "github.com/sashakoshka/arf/types"
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// LexingOperation holds information about an ongoing lexing operataion.
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type LexingOperation struct {
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file *file.File
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char rune
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tokens []Token
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}
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// Tokenize converts a file into a slice of tokens (lexemes).
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func Tokenize (file *file.File) (tokens []Token, err error) {
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lexer := LexingOperation { file: file }
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err = lexer.tokenize()
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tokens = lexer.tokens
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// if the lexing operation returned io.EOF, nothing went wrong so we
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// return nil for err.
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if err == io.EOF {
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err = nil
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}
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return
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}
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// tokenize converts a file into a slice of tokens (lexemes). It will always
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// return a non-nil error, but if nothing went wrong it will return io.EOF.
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func (lexer *LexingOperation) tokenize () (err error) {
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err = lexer.nextRune()
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if err != nil { return }
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for {
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fmt.Println(string(lexer.char))
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lowercase := lexer.char >= 'a' && lexer.char <= 'z'
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uppercase := lexer.char >= 'A' && lexer.char <= 'Z'
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number := lexer.char >= '0' && lexer.char <= '9'
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if number {
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// TODO: tokenize number begin\
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err = lexer.tokenizeNumberBeginning(false)
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if err != nil { return }
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} else if lowercase || uppercase {
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err = lexer.tokenizeAlphaBeginning()
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if err != nil { return }
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} else if lexer.char >= '0' && lexer.char <= '9' {
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err = lexer.tokenizeSymbolBeginning()
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if err != nil { return }
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}
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err = lexer.skipSpaces()
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if err != nil { return }
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}
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return
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}
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// tokenizeSymbolBeginning lexes a token that starts with a number.
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func (lexer *LexingOperation) tokenizeNumberBeginning (negative bool) (err error) {
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var number uint64
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if lexer.char == '0' {
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lexer.nextRune()
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if lexer.char == 'x' {
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lexer.nextRune()
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number, err = lexer.tokenizeHexidecimalNumber()
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} else if lexer.char == 'b' {
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lexer.nextRune()
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number, err = lexer.tokenizeBinaryNumber()
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} else if lexer.char == '.' {
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number, err = lexer.tokenizeDecimalNumber()
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} else if lexer.char >= '0' && lexer.char <= '9' {
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number, err = lexer.tokenizeOctalNumber()
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} else {
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return file.NewError (
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lexer.file.Location(), 1,
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"unexpected character in number literal",
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file.ErrorKindError)
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}
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} else {
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number, err = lexer.tokenizeDecimalNumber()
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}
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if err != nil { return }
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token := Token { }
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if negative {
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token.kind = TokenKindInt
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token.value = int64(number) * -1
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} else {
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token.kind = TokenKindUInt
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token.value = uint64(number)
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}
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lexer.addToken(token)
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return
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}
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// tokenizeHexidecimalNumber Reads and tokenizes a hexidecimal number.
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func (lexer *LexingOperation) tokenizeHexidecimalNumber () (number uint64, err error) {
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for {
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if lexer.char >= '0' && lexer.char <= '9' {
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number *= 16
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number += uint64(lexer.char - '0')
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} else if lexer.char >= 'A' && lexer.char <= 'F' {
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number *= 16
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number += uint64(lexer.char - 'A' + 9)
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} else if lexer.char >= 'a' && lexer.char <= 'f' {
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number *= 16
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number += uint64(lexer.char - 'a' + 9)
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} else {
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break
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}
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err = lexer.nextRune()
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if err != nil { return }
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}
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return
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}
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// tokenizeBinaryNumber Reads and tokenizes a binary number.
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func (lexer *LexingOperation) tokenizeBinaryNumber () (number uint64, err error) {
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for {
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if lexer.char == '0' {
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number *= 2
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} else if lexer.char == '1' {
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number *= 2
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number += 1
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} else {
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break
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}
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err = lexer.nextRune()
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if err != nil { return }
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}
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return
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}
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// tokenizeDecimalNumber Reads and tokenizes a decimal number.
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func (lexer *LexingOperation) tokenizeDecimalNumber () (number uint64, err error) {
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for lexer.char >= '0' && lexer.char <= '9' {
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number *= 10
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number += uint64(lexer.char - '0')
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err = lexer.nextRune()
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if err != nil { return }
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}
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return
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}
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// tokenizeOctalNumber Reads and tokenizes an octal number.
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func (lexer *LexingOperation) tokenizeOctalNumber () (number uint64, err error) {
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for lexer.char >= '0' && lexer.char <= '7' {
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number *= 8
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number += uint64(lexer.char - '0')
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err = lexer.nextRune()
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if err != nil { return }
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}
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return
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}
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func (lexer *LexingOperation) tokenizeAlphaBeginning () (err error) {
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got := ""
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for {
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lowercase := lexer.char >= 'a' && lexer.char <= 'z'
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uppercase := lexer.char >= 'A' && lexer.char <= 'Z'
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number := lexer.char >= '0' && lexer.char <= '9'
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if !lowercase && !uppercase && !number { break }
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got += string(lexer.char)
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lexer.nextRune()
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}
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token := Token { kind: TokenKindName, value: got }
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if len(got) == 2 {
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firstValid := got[0] == 'n' || got[0] == 'r' || got[0] == 'w'
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secondValid := got[1] == 'n' || got[1] == 'r' || got[1] == 'w'
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if firstValid && secondValid {
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token.kind = TokenKindPermission
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token.value = types.PermissionFrom(got)
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}
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}
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lexer.addToken(token)
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return
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}
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func (lexer *LexingOperation) tokenizeSymbolBeginning () (err error) {
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switch lexer.char {
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case '#':
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// comment
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for lexer.char != '\n' {
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err = lexer.nextRune()
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if err != nil { return }
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}
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case '\t':
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// indent level
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previousToken := lexer.tokens[len(lexer.tokens) - 1]
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if !previousToken.Is(TokenKindNewline) ||
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!previousToken.Is(TokenKindNewline) {
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file.NewError (
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lexer.file.Location(), 1,
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"tab not used as indent",
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file.ErrorKindWarn)
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break
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}
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for lexer.char == '\t' {
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lexer.addToken (Token {
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kind: TokenKindIndent,
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})
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err = lexer.nextRune()
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if err != nil { return }
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}
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case '\n':
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// line break
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// TODO: if last line was blank, (ony whitespace) discard.
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lexer.addToken (Token {
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kind: TokenKindNewline,
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})
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err = lexer.nextRune()
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case '"':
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// TODO: tokenize string literal
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err = lexer.nextRune()
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case '\'':
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// TODO: tokenize rune literal
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err = lexer.nextRune()
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case ':':
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lexer.addToken (Token {
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kind: TokenKindColon,
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})
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err = lexer.nextRune()
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case '.':
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lexer.addToken (Token {
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kind: TokenKindDot,
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})
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err = lexer.nextRune()
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case '[':
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lexer.addToken (Token {
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kind: TokenKindLBracket,
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})
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err = lexer.nextRune()
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case ']':
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lexer.addToken (Token {
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kind: TokenKindRBracket,
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})
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err = lexer.nextRune()
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case '{':
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lexer.addToken (Token {
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kind: TokenKindLBrace,
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})
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err = lexer.nextRune()
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case '}':
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lexer.addToken (Token {
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kind: TokenKindRBrace,
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})
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err = lexer.nextRune()
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case '+':
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// TODO: tokenize plus begin
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err = lexer.nextRune()
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case '-':
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err = lexer.tokenizeDashBeginning()
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case '*':
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lexer.addToken (Token {
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kind: TokenKindAsterisk,
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})
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err = lexer.nextRune()
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case '/':
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lexer.addToken (Token {
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kind: TokenKindSlash,
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})
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err = lexer.nextRune()
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case '@':
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lexer.addToken (Token {
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kind: TokenKindAt,
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})
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err = lexer.nextRune()
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case '!':
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lexer.addToken (Token {
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kind: TokenKindExclamation,
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})
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err = lexer.nextRune()
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case '%':
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lexer.addToken (Token {
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kind: TokenKindPercent,
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})
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err = lexer.nextRune()
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case '~':
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lexer.addToken (Token {
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kind: TokenKindTilde,
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})
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err = lexer.nextRune()
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case '<':
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// TODO: tokenize less than begin
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err = lexer.nextRune()
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case '>':
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// TODO: tokenize greater than begin
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err = lexer.nextRune()
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case '|':
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// TODO: tokenize bar begin
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err = lexer.nextRune()
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case '&':
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// TODO: tokenize and begin
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err = lexer.nextRune()
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default:
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err = file.NewError (
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lexer.file.Location(), 1,
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"unexpected symbol character " +
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string(lexer.char),
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file.ErrorKindError)
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return
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}
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return
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}
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func (lexer *LexingOperation) tokenizeDashBeginning () (err error) {
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token := Token { kind: TokenKindMinus }
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lexer.nextRune()
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if lexer.char == '-' {
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token.kind = TokenKindDecrement
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lexer.nextRune()
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} else if lexer.char == '>' {
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token.kind = TokenKindReturnDirection
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lexer.nextRune()
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}
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if lexer.char == '-' {
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token.kind = TokenKindSeparator
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lexer.nextRune()
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}
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lexer.addToken(token)
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return
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}
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// addToken adds a new token to the lexer's token slice.
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func (lexer *LexingOperation) addToken (token Token) {
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lexer.tokens = append(lexer.tokens, token)
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}
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// skipSpaces skips all space characters (not tabs or newlines)
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func (lexer *LexingOperation) skipSpaces () (err error) {
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for lexer.char == ' ' {
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err = lexer.nextRune()
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if err != nil { return }
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}
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return
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}
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// nextRune advances the lexer to the next rune in the file.
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func (lexer *LexingOperation) nextRune () (err error) {
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lexer.char, _, err = lexer.file.ReadRune()
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if err != nil && err != io.EOF {
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return file.NewError (
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lexer.file.Location(), 1,
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err.Error(), file.ErrorKindError)
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}
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return
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}
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