post-scarcity/src/peano.c

152 lines
4.5 KiB
C

/**
* peano.c
*
* Basic peano arithmetic
*
* (c) 2017 Simon Brooke <simon@journeyman.cc>
* Licensed under GPL version 2.0, or, at your option, any later version.
*/
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "consspaceobject.h"
#include "conspage.h"
#include "equal.h"
#include "integer.h"
#include "intern.h"
#include "lispops.h"
#include "print.h"
#include "read.h"
#include "real.h"
#include "stack.h"
/**
* Add an indefinite number of numbers together
* @param env the evaluation environment - ignored;
* @param frame the stack frame.
* @return a pointer to an integer or real.
*/
struct cons_pointer
lisp_add( struct stack_frame *frame, struct cons_pointer env ) {
struct cons_pointer result = NIL;
long int i_accumulator = 0;
long double d_accumulator = 0;
bool is_int = true;
for ( int i = 0; i < args_in_frame && !nilp( frame->arg[i] ); i++ ) {
struct cons_space_object current = pointer2cell( frame->arg[i] );
switch ( current.tag.value ) {
case INTEGERTV:
i_accumulator += current.payload.integer.value;
d_accumulator += numeric_value( frame->arg[i] );
break;
case REALTV:
d_accumulator += current.payload.real.value;
is_int = false;
break;
default:
lisp_throw( c_string_to_lisp_string( "Cannot add: not a number" ),
frame );
}
if ( !nilp( frame->more ) ) {
lisp_throw( c_string_to_lisp_string
( "Cannot yet add more than 8 numbers" ), frame );
}
if ( is_int ) {
result = make_integer( i_accumulator );
} else {
result = make_real( d_accumulator );
}
}
return result;
}
/**
* Multiply an indefinite number of numbers together
* @param env the evaluation environment - ignored;
* @param frame the stack frame.
* @return a pointer to an integer or real.
*/
struct cons_pointer
lisp_multiply( struct stack_frame *frame, struct cons_pointer env ) {
struct cons_pointer result = NIL;
long int i_accumulator = 1;
long double d_accumulator = 1;
bool is_int = true;
for ( int i = 0; i < args_in_frame && !nilp( frame->arg[i] ); i++ ) {
struct cons_space_object arg = pointer2cell( frame->arg[i] );
switch ( arg.tag.value ) {
case INTEGERTV:
i_accumulator *= arg.payload.integer.value;
d_accumulator *= numeric_value( frame->arg[i] );
break;
case REALTV:
d_accumulator *= arg.payload.real.value;
is_int = false;
break;
default:
lisp_throw( c_string_to_lisp_string
( "Cannot multiply: not a number" ), frame );
}
if ( !nilp( frame->more ) ) {
lisp_throw( c_string_to_lisp_string
( "Cannot yet multiply more than 8 numbers" ), frame );
}
if ( is_int ) {
result = make_integer( i_accumulator );
} else {
result = make_real( d_accumulator );
}
}
return result;
}
/**
* Subtract one number from another.
* @param env the evaluation environment - ignored;
* @param frame the stack frame.
* @return a pointer to an integer or real.
*/
struct cons_pointer
lisp_subtract( struct stack_frame *frame, struct cons_pointer env ) {
struct cons_pointer result = NIL;
struct cons_space_object arg0 = pointer2cell( frame->arg[0] );
struct cons_space_object arg1 = pointer2cell( frame->arg[1] );
if ( integerp( frame->arg[0] ) && integerp( frame->arg[1] ) ) {
result =
make_integer( arg0.payload.integer.value -
arg1.payload.integer.value );
} else if ( realp( frame->arg[0] ) && realp( frame->arg[1] ) ) {
result =
make_real( arg0.payload.real.value - arg1.payload.real.value );
} else if ( integerp( frame->arg[0] ) && realp( frame->arg[1] ) ) {
result =
make_real( numeric_value( frame->arg[0] ) -
arg1.payload.real.value );
} else if ( realp( frame->arg[0] ) && integerp( frame->arg[1] ) ) {
result =
make_real( arg0.payload.real.value -
numeric_value( frame->arg[0] ) );
} // else we have an error!
// and if not nilp[frame->arg[2]) we also have an error.
return result;
}