00058: Using BBx as a parser with input and output pipes

Title:

Using BBx as a parser with input and output pipes

Description:

The following program and Unix command line shows how to build a rudimentary parser in BBx. Because this is a simple example, it just prepends the ‘Got: ‘ string to every line received. 


BBx program: 
0005 OPEN (1)”IO” 
0010 READ (1,END=0200,TIM=5)A$ 
0020 PRINT “Got: “,A$ 
0030 GOTO 0010 
0200 RELEASE 

Example using a Unix ‘ls’ for input, parsing in BBx, piping to Unix ‘more’ 
ls | ./pro5 -tIO testpgm |more 


=================================================================================
C PROGRAM 

#include <stdio.h> 
main (void) 

{ 
int *cle[1]; 
*cle[1]=getchar(); 
printf(“cle :%s\n\n”,cle[1]); 
} 

BBx PROGRAM 

0010 ERASE “./testfile”,ERR=0020 
0020 MKEYED “./testfile”,10,10,10 
0030 OPEN (1)”./testfile” 
0040 PRINT (1,KEY=”a”)”a” 
0050 CLOSE (1) 
0060 OPEN (1)”./testfile” 
0070 READ (1,KEY=”a”)Z$ 
0080 CLOSE (1) 
0090 OPEN (1)”IO” 
0100 PRINT (1)Z$ 
0110 CLOSE (1) 
0120 RELEASE 

THE UNIX COMMAND 

$ ./pro5 -tIO testpgm.bbx | ctestpgm 
cle :a 

This example shows how the BBx program reads in data from a BBx mkeyed file, then prints it out to stdout. This output is piped to the C program, which reads it from stdin and then prints it out to show that it read the data correctly. 

=================================================================================
To modify the previous example to work with a string (as opposed to a char) replace the C and BBx programs with the following: 

C PROGRAM 

#include <stdio.h> 
main (void) 
{ 

int ch; 
printf(“The following was read from stdin:”); 
while ((ch=getchar()) != EOF) 
putchar(ch); 

} 

BBx PROGRAM 

0010 ERASE “./testfile”,ERR=0020 
0020 MKEYED “./testfile”,10,10,10 
0030 OPEN (1)”./testfile” 
0040 LET A$=”0011abcd” 
0050 PRINT (1,KEY=A$)A$ 
0060 CLOSE (1) 
0070 OPEN (1)”./testfile” 
0080 LET B$=KEY(1) 
0090 READ (1,KEY=B$)Z$ 
0100 CLOSE (1) 
0110 OPEN (1)”IO” 
0120 PRINT (1)Z$ 
0130 CLOSE (1) 
0140 RELEASE 

Last Modified: 11/10/1998 Product: PRO/5 Operating System: Unix

BASIS structures five components of their technology into the BBx Generations.