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https://github.com/RetroShare/RetroShare.git
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3be22536df
git-svn-id: http://svn.code.sf.net/p/retroshare/code/branches/v0.5-gxs-b1@5953 b45a01b8-16f6-495d-af2f-9b41ad6348cc
362 lines
9.1 KiB
Plaintext
362 lines
9.1 KiB
Plaintext
# A 'syntax-directed interpreter' (all execution is a side-effect of parsing).
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# Inspired by Dennis Allison's original Tiny BASIC grammar, circa 1975.
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#
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# Copyright (c) 2007 by Ian Piumarta
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# All rights reserved.
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#
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# Permission is hereby granted, free of charge, to any person obtaining a
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# copy of this software and associated documentation files (the 'Software'),
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# to deal in the Software without restriction, including without limitation
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# the rights to use, copy, modify, merge, publish, distribute, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, provided that the above copyright notice(s) and this
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# permission notice appear in all copies of the Software. Acknowledgement
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# of the use of this Software in supporting documentation would be
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# appreciated but is not required.
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#
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# THE SOFTWARE IS PROVIDED 'AS IS'. USE ENTIRELY AT YOUR OWN RISK.
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#
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# Last edited: 2012-04-29 15:14:06 by piumarta on emilia
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%{
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# include <stdio.h>
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typedef struct line line;
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struct line
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{
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int number;
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int length;
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char *text;
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};
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line *lines= 0;
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int numLines= 0;
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int pc= -1, epc= -1;
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int batch= 0;
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int nextline(char *buf, int max);
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# define min(x, y) ((x) < (y) ? (x) : (y))
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# define YY_INPUT(buf, result, max_size) \
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{ \
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if ((pc >= 0) && (pc < numLines)) \
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{ \
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line *linep= lines+pc++; \
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result= min(max_size, linep->length); \
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memcpy(buf, linep->text, result); \
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} \
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else \
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result= nextline(buf, max_size); \
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}
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union value {
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int number;
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char *string;
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int (*binop)(int lhs, int rhs);
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};
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# define YYSTYPE union value
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int variables[26];
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void accept(int number, char *line);
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void save(char *name);
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void load(char *name);
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void type(char *name);
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int lessThan(int lhs, int rhs) { return lhs < rhs; }
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int lessEqual(int lhs, int rhs) { return lhs <= rhs; }
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int notEqual(int lhs, int rhs) { return lhs != rhs; }
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int equalTo(int lhs, int rhs) { return lhs == rhs; }
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int greaterEqual(int lhs, int rhs) { return lhs >= rhs; }
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int greaterThan(int lhs, int rhs) { return lhs > rhs; }
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int input(void);
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int stack[1024], sp= 0;
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char *help;
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void error(char *fmt, ...);
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int findLine(int n, int create);
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%}
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line = - s:statement CR
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| - n:number < ( !CR . )* CR > { accept(n.number, yytext); }
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| - CR
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| - < ( !CR . )* CR > { epc= pc; error("syntax error"); }
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| - !. { exit(0); }
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statement = 'print'- expr-list
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| 'if'- e1:expression r:relop e2:expression { if (!r.binop(e1.number, e2.number)) yythunkpos= 0; }
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'then'- statement
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| 'goto'- e:expression { epc= pc; if ((pc= findLine(e.number, 0)) < 0) error("no such line"); }
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| 'input'- var-list
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| 'let'- v:var EQUAL e:expression { variables[v.number]= e.number; }
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| 'gosub'- e:expression { epc= pc; if (sp < 1024) stack[sp++]= pc, pc= findLine(e.number, 0); else error("too many gosubs");
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if (pc < 0) error("no such line"); }
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| 'return'- { epc= pc; if ((pc= sp ? stack[--sp] : -1) < 0) error("no gosub"); }
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| 'clear'- { while (numLines) accept(lines->number, "\n"); }
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| 'list'- { int i; for (i= 0; i < numLines; ++i) printf("%5d %s", lines[i].number, lines[i].text); }
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| 'run'- s:string { load(s.string); pc= 0; }
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| 'run'- { pc= 0; }
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| 'end'- { pc= -1; if (batch) exit(0); }
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| 'rem'- ( !CR . )*
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| ('bye'|'quit'|'exit')- { exit(0); }
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| 'save'- s:string { save(s.string); }
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| 'load'- s:string { load(s.string); }
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| 'type'- s:string { type(s.string); }
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| 'dir'- { system("ls *.bas"); }
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| 'help'- { fprintf(stderr, "%s", help); }
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expr-list = ( e:string { printf("%s", e.string); }
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| e:expression { printf("%d", e.number); }
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)? ( COMMA ( e:string { printf("%s", e.string); }
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| e:expression { printf("%d", e.number); }
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)
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)* ( COMMA
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| !COMMA { printf("\n"); }
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)
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var-list = v:var { variables[v.number]= input(); }
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( COMMA v:var { variables[v.number]= input(); }
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)*
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expression = ( PLUS? l:term
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| MINUS l:term { l.number = -l.number }
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) ( PLUS r:term { l.number += r.number }
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| MINUS r:term { l.number -= r.number }
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)* { $$.number = l.number }
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term = l:factor ( STAR r:factor { l.number *= r.number }
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| SLASH r:factor { l.number /= r.number }
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)* { $$.number = l.number }
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factor = v:var { $$.number = variables[v.number] }
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| n:number
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| OPEN expression CLOSE
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var = < [a-z] > - { $$.number = yytext[0] - 'a' }
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number = < digit+ > - { $$.number = atoi(yytext); }
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digit = [0-9]
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string = '"' < [^\"]* > '"' - { $$.string = yytext; }
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relop = '<=' - { $$.binop= lessEqual; }
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| '<>' - { $$.binop= notEqual; }
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| '<' - { $$.binop= lessThan; }
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| '>=' - { $$.binop= greaterEqual; }
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| '>' - { $$.binop= greaterThan; }
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| '=' - { $$.binop= equalTo; }
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EQUAL = '=' - CLOSE = ')' - OPEN = '(' -
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SLASH = '/' - STAR = '*' - MINUS = '-' -
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PLUS = '+' - COMMA = ',' -
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- = [ \t]*
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CR = '\n' | '\r' | '\r\n'
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%%
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#include <unistd.h>
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#include <stdarg.h>
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char *help=
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"print <num>|<string> [, <num>|<string> ...] [,]\n"
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"if <expr> <|<=|<>|=|>=|> <expr> then <stmt>\n"
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"input <var> [, <var> ...] let <var> = <expr>\n"
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"goto <expr> gosub <expr>\n"
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"end return\n"
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"list clear\n"
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"run [\"filename\"] rem <comment...>\n"
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"dir type \"filename\"\n"
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"save \"filename\" load \"filename\"\n"
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"bye|quit|exit help\n"
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;
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void error(char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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if (epc > 0)
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fprintf(stderr, "\nline %d: %s", lines[epc-1].number, lines[epc-1].text);
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else
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fprintf(stderr, "\n");
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vfprintf(stderr, fmt, ap);
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fprintf(stderr, "\n");
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va_end(ap);
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epc= pc= -1;
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}
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#ifdef USE_READLINE
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# include <readline/readline.h>
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# include <readline/history.h>
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#endif
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int nextline(char *buf, int max)
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{
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pc= -1;
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if (batch) exit(0);
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if (isatty(fileno(stdin)))
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{
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# ifdef USE_READLINE
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char *line= readline(">");
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if (line)
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{
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int len= strlen(line);
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if (len >= max) len= max - 1;
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strncpy(buf, line, len);
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(buf)[len]= '\n';
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add_history(line);
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free(line);
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return len + 1;
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}
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else
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{
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printf("\n");
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return 0;
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}
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# endif
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putchar('>');
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fflush(stdout);
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}
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return fgets(buf, max, stdin) ? strlen(buf) : 0;
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}
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int maxLines= 0;
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int findLine(int n, int create)
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{
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int lo= 0, hi= numLines - 1;
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while (lo <= hi)
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{
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int mid= (lo + hi) / 2, lno= lines[mid].number;
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if (lno > n)
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hi= mid - 1;
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else if (lno < n)
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lo= mid + 1;
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else
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return mid;
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}
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if (create)
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{
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if (numLines == maxLines)
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{
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maxLines *= 2;
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lines= realloc(lines, sizeof(line) * maxLines);
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}
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if (lo < numLines)
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memmove(lines + lo + 1, lines + lo, sizeof(line) * (numLines - lo));
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++numLines;
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lines[lo].number= n;
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lines[lo].text= 0;
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return lo;
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}
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return -1;
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}
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void accept(int n, char *s)
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{
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if (s[0] < 32) /* delete */
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{
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int lno= findLine(n, 0);
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if (lno >= 0)
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{
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if (lno < numLines - 1)
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memmove(lines + lno, lines + lno + 1, sizeof(line) * (numLines - lno - 1));
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--numLines;
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}
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}
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else /* insert */
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{
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int lno= findLine(n, 1);
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if (lines[lno].text) free(lines[lno].text);
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lines[lno].length= strlen(s);
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lines[lno].text= strdup(s);
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}
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}
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char *extend(char *name)
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{
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static char path[1024];
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int len= strlen(name);
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sprintf(path, "%s%s", name, (((len > 4) && !strcasecmp(".bas", name + len - 4)) ? "" : ".bas"));
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return path;
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}
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void save(char *name)
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{
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FILE *f= fopen(name= extend(name), "w");
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if (!f)
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perror(name);
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else
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{
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int i;
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for (i= 0; i < numLines; ++i)
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fprintf(f, "%d %s", lines[i].number, lines[i].text);
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fclose(f);
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}
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}
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void load(char *name)
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{
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FILE *f= fopen(name= extend(name), "r");
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if (!f)
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perror(name);
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else
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{
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int lineNumber;
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char lineText[1024];
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while ((1 == fscanf(f, " %d ", &lineNumber)) && fgets(lineText, sizeof(lineText), f))
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accept(lineNumber, lineText);
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fclose(f);
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}
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}
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void type(char *name)
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{
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FILE *f= fopen(name= extend(name), "r");
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if (!f)
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perror(name);
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else
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{
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int c, d;
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while ((c= getc(f)) >= 0)
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putchar(d= c);
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fclose(f);
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if ('\n' != d && '\r' != d) putchar('\n');
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}
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}
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int input(void)
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{
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char line[32];
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fgets(line, sizeof(line), stdin);
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return atoi(line);
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}
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int main(int argc, char **argv)
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{
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lines= malloc(sizeof(line) * (maxLines= 32));
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numLines= 0;
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if (argc > 1)
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{
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batch= 1;
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while (argc-- > 1)
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load(*++argv);
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pc= 0;
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}
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while (!feof(stdin))
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yyparse();
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return 0;
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}
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