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/*
* @LANG: indep
*/
/*
* Demonstrate the use of goto, call and return. This machine expects either a
* lower case char or a digit as a command then a space followed by the command
* arg. If the command is a char, then the arg must be an a string of chars.
* If the command is a digit, then the arg must be a string of digits. This
* choice is determined by action code, rather than though transition
* desitinations.
*/
char comm;
int top;
int stack[32];
%%
%%{
machine GotoCallRet;
# A reference to a state in an unused action caused a segfault in 5.8. */
action unusedAction { fentry(garble_line); }
action err_garbling_line { prints "error: garbling line\n"; }
action goto_main { fgoto main; }
action recovery_failed { prints "error: failed to recover\n"; }
# Error machine, consumes to end of
# line, then starts the main line over.
garble_line := ( (any-'\n')*'\n')
>err_garbling_line
@goto_main
$/recovery_failed;
action hold_and_return {fhold; fret;}
# Look for a string of alphas or of digits,
# on anything else, hold the character and return.
alp_comm := alpha+ $!hold_and_return;
dig_comm := digit+ $!hold_and_return;
# Choose which to machine to call into based on the command.
action comm_arg {
if ( comm >= 'a' )
fcall alp_comm;
else
fcall dig_comm;
}
# Specifies command string. Note that the arg is left out.
command = (
[a-z0-9] @{comm = fc;} ' ' @comm_arg '\n'
) @{prints "correct command\n";};
# Any number of commands. If there is an
# error anywhere, garble the line.
main := command* $!{fhold;fgoto garble_line;};
}%%
/* _____INPUT_____
"lkajsdf\n"
"2134\n"
"(\n"
"\n"
"*234234()0909 092 -234aslkf09`1 11\n"
"1\n"
"909\n"
"1 a\n"
"11 1\n"
"a 1\n"
"aa a\n"
"1 1\n"
"1 123456\n"
"a a\n"
"a abcdef\n"
"h"
"a aa1"
_____INPUT_____ */
/* _____OUTPUT_____
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
error: garbling line
ACCEPT
correct command
ACCEPT
correct command
ACCEPT
correct command
ACCEPT
correct command
ACCEPT
error: failed to recover
FAIL
error: garbling line
error: failed to recover
FAIL
_____OUTPUT_____ */
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