quakeforge/ruamoko/scheme/Lexer.r

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R
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#include "Lexer.h"
#include "Number.h"
#include "string.h"
#include "Boolean.h"
#include "Error.h"
#include "defs.h"
BOOL isdigit (string x)
{
return (x == "0" || x == "1" || x == "2" || x == "3" ||
x == "4" || x == "5" || x == "6" || x == "7" ||
x == "8" || x == "9");
}
BOOL isspace (string x)
{
return (x == " " || x == "\t" || x == "\n" || x == "\r");
}
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BOOL isjunk (string x)
{
return isspace (x) || x == ";";
}
BOOL issymbol (string x)
{
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return (x != "" && x != "(" && x !=")" && !isjunk (x));
}
@implementation Lexer
+ (id) newFromSource: (string) s file: (string) f
{
return [[Lexer alloc] initWithSource: s file: f];
}
- (id) initWithSource: (string) s file: (string) f
{
self = [super init];
source = str_new();
str_copy(source, s);
filename = f;
linenum = 1;
return self;
}
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- (SchemeObject*) nextToken
{
local int len;
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local Number *num;
local Symbol *sym;
local String *str;
local Boolean *bl;
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for (len = 0; isjunk(str_mid(source, len, len+1)); len++) {
if (str_mid(source, len, len+1) == ";") {
while (str_mid(source, len, len+1) != "\n") {
len++;
}
}
if (str_mid(source, len, len+1) == "\n") {
linenum++;
}
}
str_copy (source, str_mid(source, len));
switch (str_mid (source, 0, 1)) {
case "(":
str_copy (source, str_mid (source, 1));
return [Symbol leftParen];
case ")":
str_copy (source, str_mid (source, 1));
return [Symbol rightParen];
case "0": case "1": case "2":
case "3": case "4": case "5":
case "6": case "7": case "8":
case "9":
for (len = 1; isdigit(str_mid(source, len, len+1)); len++);
num = [Number newFromInt: stoi (str_mid(source, 0, len))];
[num source: filename];
[num line: linenum];
str_copy (source, str_mid(source, len));
return num;
case "\"":
for (len = 1; str_mid(source, len, len+1) != "\""; len++);
str = [String newFromString: str_mid(source, 1, len)];
[str source: filename];
[str line: linenum];
str_copy (source, str_mid(source, len+1));
return str;
case "'":
str_copy (source, str_mid (source, 1));
return [Symbol quote];
case ".":
str_copy (source, str_mid (source, 1));
return [Symbol dot];
case "#":
str_copy (source, str_mid (source, 1));
switch (str_mid (source, 0, 1)) {
case "t":
bl = [Boolean trueConstant];
str_copy (source, str_mid (source, 1));
return bl;
case "f":
bl = [Boolean falseConstant];
str_copy (source, str_mid (source, 1));
return bl;
default:
return [Error type: "parse"
message: "Invalid # constant"
by: self];
}
case "":
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return nil;
default:
for (len = 1; issymbol(str_mid(source, len, len+1)); len++);
sym = [Symbol forString: str_mid (source, 0, len)];
str_copy (source, str_mid(source, len));
return sym;
}
}
- (int) lineNumber
{
return linenum;
}
- (int) line
{
return linenum;
}
- (string) source
{
return filename;
}
@end