About Promela Language SPIN

How I can fix these error

spin: model.pml:$8,$ Error: syntax error saw $\text{'}$an identifier' near 'person'

spin: model.pml:$12,$ Error: syntax error saw $\text{'}$an identifier' near 'person'

spin: model.pml:$26,$ Error: no field 'changed' defined in structure 'persons'

saw 'operator: $=\text{'}$

spin: model.pml:$28,$ Error: no field $\text{'}$d$\text{'}$ defined in structure 'persons'

saw $\text{'}->\text{'}$ near 'persons'

spin: model.pml:$28,$ Error: no field $\text{'}$d$\text{'}$ defined in structure 'persons'

saw 'operator: $=\text{'}$

spin: model.pml:$28,$ Error: no field 'changed' defined in structure 'persons'

saw 'operator: $=\text{'}$

spin: model.pml:$31,$ Error: syntax error saw 'inline name'

spin: model.pml:$33,$ Error: undeclared variable: new$\_$d saw 'operator: $!=\text{'}$

Programming

#define P $3//$ number of people

typedef struct $\{$

int a; $//$ availability interval

int b; $//$ initial offset

int d; $//$ candidate date

bool changed; $//$ flag to indicate if di was updated

$\}$ person;

chan to$[$P$]=[1]$ of $\{$ int $\}$;

person persons$[$P$]$;

bool terminated$[$P$]$; $//$ array to track termination status

inline f$($i$,$ t$)\{$

if

:: $($t $<$ persons$[$i$].$b$)->$ return persons$[$i$].$b;

:: else $->$ return $(($t $-$ persons$[$i$].$b $+$ persons$[$i$].$a$)/$ persons$[$i$].$a$)*$ persons$[$i$].$a $+$ persons$[$i$].$b;

fi;

$\}$

proctype Person$($byte i$)\{$

int t;

do

:: to$[$i$]?$ t $->$

persons$[$i$].$changed $=$ false;

if

:: t $>$ persons$[$i$].$d $->$ persons$[$i$].$d $=$ t; persons$[$i$].$changed $=$ true;

:: else $->$ skip;

fi;

int new$\_$d $=$ f$($i$,$ persons$[$i$].$d$)$;

if

:: new$\_$d $!=$ persons$[$i$].$d $->$ persons$[$i$].$d $=$ new$\_$d; persons$[$i$].$changed $=$ true;

:: else $->$ skip;

fi;

to$[($i $+1)\%$ P$]!$ persons$[$i$].$d;

terminated$[$i$]=!$persons$[$i$].$changed;

if

:: terminated$[0]$ && terminated$[1]$ && terminated$[2]->$ break;

:: else $->$ skip;

fi;

od;

$\}$

init $\{$

atomic $\{$

$//$ initialize persons with a$1=5,$ a$2=6,$ a$3=7$

persons$[0].$a $=5$; persons$[1].$a $=6$; persons$[2].$a $=7$;

$//$ unknown initial offsets, b$1,$ b$2,$ b$3$

persons$[0].$b $=0$; persons$[1].$b $=0$; persons$[2].$b $=0$; $//$ these will vary

$//$ initial candidate dates

persons$[0].$d $=0$; persons$[1].$d $=0$; persons$[2].$d $=0$;

$//$ start the processes

run Person$(0)$;

run Person$(1)$;

run Person$(2)$;

$//$ initiate communication

to$[0]!0$;

$\}$

$\}$