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|
%union
{
double u_val;
double *u_symbol;
double (*u_fun)(double);
}
%token <u_val> NUM // Simple double precision number
%token <u_symbol> VAR // Variable
%token <u_fun> FNCT // Function
%type <u_val> exp
%right '='
%left '-' '+'
%left '*' '/'
%left NEG // negation--unary minus
%right '^' // exponentiation
%%
//GRAMMAR
input:
// empty
|
input line
;
//LINE
line:
'\n'
|
exp '\n'
{
cout << "\t" << $1 << endl;
}
|
error '\n'
;
//=
exp:
NUM
|
VAR
{
$$ = *$1;
}
|
VAR '=' exp
{
$$ = *$1 = $3;
}
|
FNCT '(' exp ')'
{
$$ = (*$1)($3);
}
|
exp '+' exp
{
$$ = $1 + $3;
}
|
exp '-' exp
{
$$ = $1 - $3;
}
|
exp '*' exp
{
$$ = $1 * $3;
}
|
exp '/' exp
{
$$ = $1 / $3;
}
|
'-' exp %prec NEG
{
$$ = -$2;
}
|
// Exponentiation:
exp '^' exp
{
$$ = pow($1, $3);
}
|
'(' exp ')'
{
$$ = $2;
}
;
//=
|
