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Simplify lexer a bit.

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This commit is contained in:
Bob Nystrom
2013-11-19 20:19:02 -08:00
parent fe48113054
commit 32d41e2d54
1 changed files with 29 additions and 64 deletions
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93
src/compiler.c
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@ -228,6 +228,20 @@ static void makeToken(Parser* parser, TokenType type)
parser->current.line = parser->currentLine;
}
// If the current character is [c], then consumes it and makes a token of type
// [two]. Otherwise makes a token of type [one].
static void twoCharToken(Parser* parser, char c, TokenType two, TokenType one)
{
if (peekChar(parser) == c)
{
nextChar(parser);
makeToken(parser, two);
return;
}
makeToken(parser, one);
}
// Skips the rest of the current line.
static void skipLineComment(Parser* parser)
{
@ -269,19 +283,13 @@ static void skipBlockComment(Parser* parser)
}
}
// Skips forward until a non-whitespace character is reached.
static void skipWhitespace(Parser* parser)
{
while (peekChar(parser) == ' ') nextChar(parser);
}
// Returns non-zero if the current token's text matches [keyword].
static int isKeyword(Parser* parser, const char* keyword)
{
size_t length = parser->currentChar - parser->tokenStart;
size_t keywordLength = strlen(keyword);
return length == keywordLength &&
strncmp(parser->source + parser->tokenStart, keyword, length) == 0;
strncmp(parser->source + parser->tokenStart, keyword, length) == 0;
}
// Finishes lexing a number literal.
@ -304,7 +312,6 @@ static void readNumber(Parser* parser)
// Finishes lexing an identifier. Handles reserved words.
static void readName(Parser* parser)
{
// TODO(bob): Handle EOF.
while (isName(peekChar(parser)) || isDigit(peekChar(parser)))
{
nextChar(parser);
@ -364,11 +371,13 @@ static void readRawToken(Parser* parser)
skipLineComment(parser);
break;
}
else if (peekChar(parser) == '*')
if (peekChar(parser) == '*')
{
skipBlockComment(parser);
break;
}
makeToken(parser, TOKEN_SLASH);
return;
@ -386,75 +395,27 @@ static void readRawToken(Parser* parser)
return;
case '|':
if (peekChar(parser) == '|')
{
nextChar(parser);
makeToken(parser, TOKEN_PIPEPIPE);
}
else
{
makeToken(parser, TOKEN_PIPE);
}
twoCharToken(parser, '|', TOKEN_PIPEPIPE, TOKEN_PIPE);
return;
case '&':
if (peekChar(parser) == '&')
{
nextChar(parser);
makeToken(parser, TOKEN_AMPAMP);
}
else
{
makeToken(parser, TOKEN_AMP);
}
twoCharToken(parser, '&', TOKEN_AMPAMP, TOKEN_AMP);
return;
case '=':
if (peekChar(parser) == '=')
{
nextChar(parser);
makeToken(parser, TOKEN_EQEQ);
}
else
{
makeToken(parser, TOKEN_EQ);
}
twoCharToken(parser, '=', TOKEN_EQEQ, TOKEN_EQ);
return;
case '<':
if (peekChar(parser) == '=')
{
nextChar(parser);
makeToken(parser, TOKEN_LTEQ);
}
else
{
makeToken(parser, TOKEN_LT);
}
twoCharToken(parser, '=', TOKEN_LTEQ, TOKEN_LT);
return;
case '>':
if (peekChar(parser) == '=')
{
nextChar(parser);
makeToken(parser, TOKEN_GTEQ);
}
else
{
makeToken(parser, TOKEN_GT);
}
twoCharToken(parser, '=', TOKEN_GTEQ, TOKEN_GT);
return;
case '!':
if (peekChar(parser) == '=')
{
nextChar(parser);
makeToken(parser, TOKEN_BANGEQ);
}
else
{
makeToken(parser, TOKEN_BANG);
}
twoCharToken(parser, '=', TOKEN_BANGEQ, TOKEN_BANG);
return;
case '\n':
@ -462,7 +423,11 @@ static void readRawToken(Parser* parser)
makeToken(parser, TOKEN_LINE);
return;
case ' ': skipWhitespace(parser); break;
case ' ':
// Skip forward until we run out of whitespace.
while (peekChar(parser) == ' ') nextChar(parser);
break;
case '"': readString(parser); return;
default: