Parsing in Embedded Systems

vijay wibbled on Tuesday 02 March 2010 06:02

:-)

It's an old children's party game, "Parse the parcel", AKA, "Chinese Whispers".

Each person hears a whisper, tries to understand it, and then passes it along as a whisper. At the end of the line, the arrived message is compared with the original.

:-)

Parsers can be many things, but they can be very simple. Here's a list parser, which will use the characters in Sep to return a list of tokens ... the Lst_t library is left as exercise for student (so as not to do

Lst_t *tokens ;

tokens = s_parse( "This is my string", " \t\r" ) ; lst_dump( tokens ) ;

produces ... This is my string

Lst_t *s_parse( Str_t Str, Str_t Sep ){ Str_t p, q ; Lst_t *x ;

if( !Str ) return( (Lst_t *) NULL ) ;

x = lst_create( 10 ) ; p = Str ; while( (q = (Str_t) strsep( (Str_t *) &p, Sep )) ){ if( s_length( q ) ) lst_add( x, q ) ; } return x ; }

HTH, Rob Sciuk