shell/shell.org.y at master · dennis3124/shell · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102

/*
 * CS-252
 * shell.y: parser for shell
 *
 * This parser compiles the following grammar:
 *
 *	cmd [arg]* [> filename]
 *
 * you must extend it to understand the complete shell grammar
 *
 */

%token	<string_val> WORD

%token 	NOTOKEN GREAT NEWLINE GREATGREAT PIPE AMPERSAND GREATGREATAMPERSAND GREATAMPERSAND LESS

%union	{
		char   *string_val;
	}

%{
//#define yylex yylex
#include <stdio.h>
#include "command.h"
void yyerror(const char * s);
int yylex();

%}

%%


commands:
	command
	| commands command
	;

command: simple_command
        ;

simple_command:
	command_and_args iomodifier_opt NEWLINE {
		printf("   Yacc: Execute command\n");
		Command::_currentCommand.execute();
	}
	| NEWLINE
	| error NEWLINE { yyerrok; }
	;

command_and_args:
	command_word argument_list {
		Command::_currentCommand.
			insertSimpleCommand( Command::_currentSimpleCommand );
	}
	;

argument_list:
	argument_list argument
	| /* can be empty */
	;

argument:
	WORD {
               printf("   Yacc: insert argument \"%s\"\n", $1);

	       Command::_currentSimpleCommand->insertArgument( $1 );\
	}
	;

command_word:
	WORD {
               printf("   Yacc: insert command \"%s\"\n", $1);

	       Command::_currentSimpleCommand = new SimpleCommand();
	       Command::_currentSimpleCommand->insertArgument( $1 );
	}
	;

iomodifier_opt:
	GREAT WORD {
		printf("   Yacc: insert output \"%s\"\n", $2);
		Command::_currentCommand._outFile = $2;
	}
	| /* can be empty */
	;


%%

void
yyerror(const char * s)
{
	fprintf(stderr,"%s", s);
}

#if 0
main()
{
	yyparse();
}
#endif