mirror of
https://git.code.sf.net/p/quake/quakeforge
synced 2024-11-05 20:50:43 +00:00
80 lines
2 KiB
R
80 lines
2 KiB
R
#include "Lexer.h"
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#include "Number.h"
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#include "string.h"
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BOOL isdigit (string x)
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{
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return (x == "0" || x == "1" || x == "2" || x == "3" ||
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x == "4" || x == "5" || x == "6" || x == "7" ||
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x == "8" || x == "9");
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}
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BOOL isspace (string x)
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{
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return (x == " " || x == "\t" || x == "\n" || x == "\r");
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}
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BOOL issymbol (string x)
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{
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return (x != "" && x != "(" && x !=")" && !isspace (x));
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}
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@implementation Lexer
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+ (id) newFromSource: (string) s
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{
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return [[Lexer alloc] initWithSource: s];
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}
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- (id) initWithSource: (string) s
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{
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self = [super init];
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source = s;
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return self;
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}
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- (SchemeObject) nextToken
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{
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local integer len;
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local Number num;
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local Symbol sym;
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local String str;
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for (len = 0; isspace(str_mid(source, len, len+1)); len++);
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source = str_mid(source, len);
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switch (str_mid (source, 0, 1)) {
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case "(":
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source = str_mid (source, 1);
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return [Symbol leftParen];
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case ")":
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source = str_mid (source, 1);
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return [Symbol rightParen];
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case "0": case "1": case "2":
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case "3": case "4": case "5":
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case "6": case "7": case "8":
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case "9":
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for (len = 1; isdigit(str_mid(source, len, len+1)); len++);
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num = [Number newFromInt: stoi (str_mid(source, 0, len))];
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source = str_mid(source, len);
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return num;
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case "\"":
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for (len = 1; str_mid(source, len, len+1) != "\""; len++);
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str = [String newFromString: str_mid(source, 1, len)];
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source = str_mid(source, len+1);
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return str;
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case "'":
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source = str_mid (source, 1);
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return [Symbol quote];
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case "":
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return NIL;
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default:
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for (len = 1; issymbol(str_mid(source, len, len+1)); len++);
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sym = [Symbol forString: str_mid (source, 0, len)];
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source = str_mid(source, len);
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return sym;
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}
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}
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@end
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