140 lines
3.6 KiB
R
140 lines
3.6 KiB
R
#include "Lexer.h"
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#include "Number.h"
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#include "string.h"
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#include "Boolean.h"
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#include "Error.h"
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#include "defs.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 isjunk (string x)
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{
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return isspace (x) || x == ";";
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}
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BOOL issymbol (string x)
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{
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return (x != "" && x != "(" && x !=")" && !isjunk (x));
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}
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@implementation Lexer
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+ (id) newFromSource: (string) s file: (string) f
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{
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return [[Lexer alloc] initWithSource: s file: f];
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}
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- (id) initWithSource: (string) s file: (string) f
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{
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self = [super init];
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source = str_new();
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str_copy(source, s);
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filename = f;
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linenum = 1;
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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 int 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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local Boolean *bl;
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for (len = 0; isjunk(str_mid(source, len, len+1)); len++) {
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if (str_mid(source, len, len+1) == ";") {
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while (str_mid(source, len, len+1) != "\n") {
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len++;
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}
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}
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if (str_mid(source, len, len+1) == "\n") {
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linenum++;
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}
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}
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str_copy (source, str_mid(source, len));
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switch (str_mid (source, 0, 1)) {
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case "(":
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str_copy (source, str_mid (source, 1));
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return [Symbol leftParen];
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case ")":
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str_copy (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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[num source: filename];
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[num line: linenum];
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str_copy (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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[str source: filename];
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[str line: linenum];
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str_copy (source, str_mid(source, len+1));
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return str;
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case "'":
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str_copy (source, str_mid (source, 1));
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return [Symbol quote];
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case ".":
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str_copy (source, str_mid (source, 1));
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return [Symbol dot];
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case "#":
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str_copy (source, str_mid (source, 1));
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switch (str_mid (source, 0, 1)) {
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case "t":
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bl = [Boolean trueConstant];
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str_copy (source, str_mid (source, 1));
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return bl;
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case "f":
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bl = [Boolean falseConstant];
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str_copy (source, str_mid (source, 1));
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return bl;
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default:
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return [Error type: "parse"
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message: "Invalid # constant"
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by: self];
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}
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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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str_copy (source, str_mid(source, len));
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return sym;
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}
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}
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- (int) lineNumber
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{
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return linenum;
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}
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- (int) line
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{
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return linenum;
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}
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- (string) source
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{
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return filename;
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}
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@end
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