tdpeuter/2025LogProg-project-GhentProlog
tdpeuter/2025LogProg-project-GhentProlog
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feat(lexer): Parentheses and quoted strings

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This commit is contained in:
Tibo De Peuter 2025-03-27 18:16:53 +01:00
parent e1f632ca40
commit dc9e43e9ba
Signed by: tdpeuter
GPG key ID: 38297DE43F75FFE2
4 changed files with 155 additions and 23 deletions
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32
src/lexer/Lexer.kt
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@ -10,7 +10,10 @@ class Lexer(private val source: String) {
while (hasNext()) {
val char: Char = peek()
tokens += when {
char == '.' -> scanDot()
char == '(' -> scanSymbol(TokenType.LEFT_PARENTHESES)
char == ')' -> scanSymbol(TokenType.RIGHT_PARENTHESES)
char == '.' -> scanSymbol(TokenType.DOT)
char == '"' -> scanQuotedString()
char.isLetterOrDigit() -> scanAlphanumeric()
char.isWhitespace() -> { scanWhitespace(); continue }
else -> throw Error("Unknown symbol: $char", position)
@ -45,26 +48,39 @@ class Lexer(private val source: String) {
// Scanners
private fun scanDot(): Token {
return Token(TokenType.DOT, next().toString(), getPosition(1))
private fun scanSymbol(tokenType: TokenType): Token {
return Token(tokenType, next().toString(), getPosition(1))
}
private fun scanAlphanumeric(): Token {
var length = 0
var value = ""
while (hasNext() && peek().isLetterOrDigit()) {
value += next()
next()
length++
}
val value = source.substring(position.offset - length, position.offset)
return Token(TokenType.ALPHANUMERIC, value, getPosition(length))
}
private fun scanQuotedString(): Token {
if (next() != '"') {
throw Error("Illegal state: Expected opening quote", position)
}
var length = 0
while (hasNext() && peek() != '"') {
next()
length++
}
if (next() != '"') {
throw Error("Illegal state: Expected closing quote", position)
}
val value = source.substring(position.offset - length - 1, position.offset - 1)
return Token(TokenType.ALPHANUMERIC, value, getPosition(length))
}
private fun scanWhitespace() {
while (hasNext() && peek().isWhitespace()) {
val char = next()
if (char == '\n') {
if (next() == '\n') {
position.line++
position.column = 0
}