637 lines
22 KiB
C
637 lines
22 KiB
C
/*
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* peano.c
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*
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* Basic peano arithmetic
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*
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* (c) 2017 Simon Brooke <simon@journeyman.cc>
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* Licensed under GPL version 2.0, or, at your option, any later version.
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*/
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#include <ctype.h>
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#include <math.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "consspaceobject.h"
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#include "conspage.h"
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#include "debug.h"
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#include "equal.h"
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#include "integer.h"
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#include "intern.h"
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#include "lispops.h"
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#include "print.h"
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#include "ratio.h"
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#include "read.h"
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#include "real.h"
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#include "stack.h"
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long double to_long_double( struct cons_pointer arg );
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int64_t to_long_int( struct cons_pointer arg );
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struct cons_pointer add_2( struct stack_frame *frame,
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struct cons_pointer frame_pointer,
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struct cons_pointer arg1,
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struct cons_pointer arg2 );
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bool zerop( struct cons_pointer arg ) {
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bool result = false;
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struct cons_space_object cell = pointer2cell( arg );
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switch ( cell.tag.value ) {
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case INTEGERTV:
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result = cell.payload.integer.value == 0;
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break;
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case RATIOTV:
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result = zerop( cell.payload.ratio.dividend );
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break;
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case REALTV:
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result = ( cell.payload.real.value == 0 );
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break;
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}
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return result;
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}
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/**
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* TODO: cannot throw an exception out of here, which is a problem
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* if a ratio may legally have zero as a divisor, or something which is
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* not a number is passed in.
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*/
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long double to_long_double( struct cons_pointer arg ) {
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long double result = 0; /* not a number, as a long double */
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struct cons_space_object cell = pointer2cell( arg );
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switch ( cell.tag.value ) {
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case INTEGERTV:
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result = ( double ) cell.payload.integer.value;
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break;
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case RATIOTV:
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{
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struct cons_space_object dividend =
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pointer2cell( cell.payload.ratio.dividend );
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struct cons_space_object divisor =
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pointer2cell( cell.payload.ratio.divisor );
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result =
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( long double ) dividend.payload.integer.value /
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divisor.payload.integer.value;
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}
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break;
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case REALTV:
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result = cell.payload.real.value;
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break;
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default:
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result = NAN;
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break;
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}
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debug_print( L"to_long_double( ", DEBUG_ARITH );
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debug_print_object( arg, DEBUG_ARITH );
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debug_printf( DEBUG_ARITH, L") => %lf\n", result );
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return result;
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}
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/**
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* TODO: cannot throw an exception out of here, which is a problem
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* if a ratio may legally have zero as a divisor, or something which is
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* not a number (or is a big number) is passed in.
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*/
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int64_t to_long_int( struct cons_pointer arg ) {
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int64_t result = 0;
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struct cons_space_object cell = pointer2cell( arg );
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switch ( cell.tag.value ) {
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case INTEGERTV:
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result = cell.payload.integer.value;
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break;
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case RATIOTV:
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result = lroundl( to_long_double( arg ) );
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break;
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case REALTV:
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result = lroundl( cell.payload.real.value );
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break;
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}
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return result;
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}
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/**
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* return a cons_pointer indicating a number which is the sum of
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* the numbers indicated by `arg1` and `arg2`.
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*/
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struct cons_pointer add_2( struct stack_frame *frame,
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struct cons_pointer frame_pointer,
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struct cons_pointer arg1,
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struct cons_pointer arg2 ) {
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struct cons_pointer result;
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struct cons_space_object cell1 = pointer2cell( arg1 );
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struct cons_space_object cell2 = pointer2cell( arg2 );
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debug_print( L"add_2( arg1 = ", DEBUG_ARITH );
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debug_print_object( arg1, DEBUG_ARITH );
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debug_print( L"; arg2 = ", DEBUG_ARITH );
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debug_print_object( arg2, DEBUG_ARITH );
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debug_print( L"\n", DEBUG_ARITH );
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if ( zerop( arg1 ) ) {
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result = arg2;
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} else if ( zerop( arg2 ) ) {
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result = arg1;
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} else {
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switch ( cell1.tag.value ) {
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case EXCEPTIONTV:
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result = arg1;
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break;
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case INTEGERTV:
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switch ( cell2.tag.value ) {
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case EXCEPTIONTV:
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result = arg2;
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break;
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case INTEGERTV:
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result = make_integer( cell1.payload.integer.value +
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cell2.payload.integer.value );
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break;
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case RATIOTV:
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result =
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add_integer_ratio( frame_pointer, arg1, arg2 );
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break;
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case REALTV:
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result =
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make_real( to_long_double( arg1 ) +
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to_long_double( arg2 ) );
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break;
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default:
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result = throw_exception( c_string_to_lisp_string
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( L"Cannot add: not a number" ),
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frame_pointer );
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break;
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}
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break;
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case RATIOTV:
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switch ( cell2.tag.value ) {
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case EXCEPTIONTV:
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result = arg2;
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break;
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case INTEGERTV:
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result =
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add_integer_ratio( frame_pointer, arg2, arg1 );
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break;
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case RATIOTV:
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result = add_ratio_ratio( frame_pointer, arg1, arg2 );
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break;
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case REALTV:
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result =
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make_real( to_long_double( arg1 ) +
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to_long_double( arg2 ) );
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break;
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default:
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result = throw_exception( c_string_to_lisp_string
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( L"Cannot add: not a number" ),
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frame_pointer );
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break;
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}
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break;
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case REALTV:
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result =
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make_real( to_long_double( arg1 ) +
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to_long_double( arg2 ) );
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break;
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default:
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result = exceptionp( arg2 ) ? arg2 :
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throw_exception( c_string_to_lisp_string
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( L"Cannot add: not a number" ),
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frame_pointer );
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}
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}
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debug_print( L"}; => ", DEBUG_ARITH );
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debug_print_object( arg2, DEBUG_ARITH );
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debug_print( L"\n", DEBUG_ARITH );
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return result;
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}
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/**
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* Add an indefinite number of numbers together
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* @param env the evaluation environment - ignored;
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* @param frame the stack frame.
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* @return a pointer to an integer or real.
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*/
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struct cons_pointer lisp_add( struct stack_frame
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*frame, struct cons_pointer frame_pointer, struct
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cons_pointer env ) {
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struct cons_pointer result = make_integer( 0 );
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struct cons_pointer tmp;
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for ( int i = 0;
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i < args_in_frame &&
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!nilp( frame->arg[i] ) && !exceptionp( result ); i++ ) {
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tmp = result;
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result = add_2( frame, frame_pointer, result, frame->arg[i] );
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if ( !eq( tmp, result ) ) {
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dec_ref( tmp );
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}
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}
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struct cons_pointer more = frame->more;
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while ( consp( more ) && !exceptionp( result ) ) {
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tmp = result;
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result = add_2( frame, frame_pointer, result, c_car( more ) );
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if ( !eq( tmp, result ) ) {
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dec_ref( tmp );
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}
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more = c_cdr( more );
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}
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return result;
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}
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/**
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* return a cons_pointer indicating a number which is the product of
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* the numbers indicated by `arg1` and `arg2`.
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*/
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struct cons_pointer multiply_2( struct stack_frame *frame,
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struct cons_pointer frame_pointer,
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struct cons_pointer arg1,
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struct cons_pointer arg2 ) {
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struct cons_pointer result;
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struct cons_space_object cell1 = pointer2cell( arg1 );
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struct cons_space_object cell2 = pointer2cell( arg2 );
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debug_print( L"multiply_2( arg1 = ", DEBUG_ARITH );
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debug_print_object( arg1, DEBUG_ARITH );
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debug_print( L"; arg2 = ", DEBUG_ARITH );
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debug_print_object( arg2, DEBUG_ARITH );
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debug_print( L")", DEBUG_ARITH );
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if ( zerop( arg1 ) ) {
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result = arg2;
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} else if ( zerop( arg2 ) ) {
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result = arg1;
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} else {
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switch ( cell1.tag.value ) {
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case EXCEPTIONTV:
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result = arg1;
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break;
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case INTEGERTV:
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switch ( cell2.tag.value ) {
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case EXCEPTIONTV:
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result = arg2;
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break;
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case INTEGERTV:
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result = make_integer( cell1.payload.integer.value *
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cell2.payload.integer.value );
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break;
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case RATIOTV:
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result =
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multiply_integer_ratio( frame_pointer, arg1,
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arg2 );
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break;
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case REALTV:
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result =
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make_real( to_long_double( arg1 ) *
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to_long_double( arg2 ) );
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break;
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default:
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result = throw_exception( c_string_to_lisp_string
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( L"Cannot multiply: not a number" ),
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frame_pointer );
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break;
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}
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break;
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case RATIOTV:
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switch ( cell2.tag.value ) {
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case EXCEPTIONTV:
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result = arg2;
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break;
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case INTEGERTV:
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result =
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multiply_integer_ratio( frame_pointer, arg2,
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arg1 );
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break;
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case RATIOTV:
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result =
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multiply_ratio_ratio( frame_pointer, arg1, arg2 );
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break;
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case REALTV:
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result =
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make_real( to_long_double( arg1 ) *
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to_long_double( arg2 ) );
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break;
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default:
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result = throw_exception( c_string_to_lisp_string
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( L"Cannot multiply: not a number" ),
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frame_pointer );
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}
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break;
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case REALTV:
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result = exceptionp( arg2 ) ? arg2 :
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make_real( to_long_double( arg1 ) *
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to_long_double( arg2 ) );
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break;
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default:
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result = throw_exception( c_string_to_lisp_string
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( L"Cannot multiply: not a number" ),
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frame_pointer );
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break;
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}
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}
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debug_print( L" => ", DEBUG_ARITH );
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debug_print_object( arg2, DEBUG_ARITH );
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debug_print( L"\n", DEBUG_ARITH );
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return result;
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}
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/**
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* Multiply an indefinite number of numbers together
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* @param env the evaluation environment - ignored;
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* @param frame the stack frame.
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* @return a pointer to an integer or real.
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*/
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struct cons_pointer lisp_multiply( struct
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stack_frame
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*frame, struct cons_pointer frame_pointer, struct
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cons_pointer env ) {
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struct cons_pointer result = make_integer( 1 );
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struct cons_pointer tmp;
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for ( int i = 0; i < args_in_frame && !nilp( frame->arg[i] )
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&& !exceptionp( result ); i++ ) {
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tmp = result;
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result = multiply_2( frame, frame_pointer, result, frame->arg[i] );
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if ( !eq( tmp, result ) ) {
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dec_ref( tmp );
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}
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}
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struct cons_pointer more = frame->more;
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while ( consp( more )
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&& !exceptionp( result ) ) {
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tmp = result;
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result = multiply_2( frame, frame_pointer, result, c_car( more ) );
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if ( !eq( tmp, result ) ) {
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dec_ref( tmp );
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}
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more = c_cdr( more );
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}
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return result;
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}
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/**
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* return a cons_pointer indicating a number which is the
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* inverse of the number indicated by `arg`.
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*/
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struct cons_pointer inverse( struct cons_pointer frame,
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struct cons_pointer arg ) {
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struct cons_pointer result = NIL;
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struct cons_space_object cell = pointer2cell( arg );
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switch ( cell.tag.value ) {
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case EXCEPTIONTV:
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result = arg;
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break;
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case INTEGERTV:
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result = make_integer( 0 - to_long_int( arg ) );
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break;
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case NILTV:
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result = TRUE;
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break;
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case RATIOTV:
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result = make_ratio( frame,
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make_integer( 0 -
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to_long_int( cell.payload.
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ratio.dividend ) ),
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cell.payload.ratio.divisor );
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break;
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case REALTV:
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result = make_real( 0 - to_long_double( arg ) );
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break;
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case TRUETV:
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result = NIL;
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break;
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}
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return result;
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}
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/**
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* Subtract one number from another.
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* @param env the evaluation environment - ignored;
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* @param frame the stack frame.
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* @return a pointer to an integer or real.
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*/
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struct cons_pointer lisp_subtract( struct
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stack_frame
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*frame, struct cons_pointer frame_pointer, struct
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cons_pointer env ) {
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struct cons_pointer result = NIL;
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struct cons_space_object cell0 = pointer2cell( frame->arg[0] );
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struct cons_space_object cell1 = pointer2cell( frame->arg[1] );
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switch ( cell0.tag.value ) {
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case EXCEPTIONTV:
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result = frame->arg[0];
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break;
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case INTEGERTV:
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switch ( cell1.tag.value ) {
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case EXCEPTIONTV:
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result = frame->arg[1];
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break;
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case INTEGERTV:
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result = make_integer( cell0.payload.integer.value
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- cell1.payload.integer.value );
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break;
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case RATIOTV:{
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struct cons_pointer tmp =
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make_ratio( frame_pointer, frame->arg[0],
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make_integer( 1 ) );
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inc_ref( tmp );
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result =
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subtract_ratio_ratio( frame_pointer, tmp,
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frame->arg[1] );
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dec_ref( tmp );
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}
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break;
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case REALTV:
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result =
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make_real( to_long_double( frame->arg[0] ) -
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to_long_double( frame->arg[1] ) );
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break;
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default:
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result = throw_exception( c_string_to_lisp_string
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( L"Cannot subtract: not a number" ),
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frame_pointer );
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break;
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}
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break;
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case RATIOTV:
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switch ( cell1.tag.value ) {
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case EXCEPTIONTV:
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result = frame->arg[1];
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break;
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case INTEGERTV:{
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struct cons_pointer tmp =
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make_ratio( frame_pointer, frame->arg[1],
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make_integer( 1 ) );
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inc_ref( tmp );
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result =
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subtract_ratio_ratio( frame_pointer, frame->arg[0],
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tmp );
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dec_ref( tmp );
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}
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break;
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case RATIOTV:
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result =
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subtract_ratio_ratio( frame_pointer, frame->arg[0],
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frame->arg[1] );
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break;
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case REALTV:
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result =
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make_real( to_long_double( frame->arg[0] ) -
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to_long_double( frame->arg[1] ) );
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break;
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default:
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result = throw_exception( c_string_to_lisp_string
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( L"Cannot subtract: not a number" ),
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frame_pointer );
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break;
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}
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break;
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case REALTV:
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result = exceptionp( frame->arg[1] ) ? frame->arg[1] :
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make_real( to_long_double( frame->arg[0] ) -
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to_long_double( frame->arg[1] ) );
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break;
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default:
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result = throw_exception( c_string_to_lisp_string
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( L"Cannot subtract: not a number" ),
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frame_pointer );
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break;
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}
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// and if not nilp[frame->arg[2]) we also have an error.
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return result;
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}
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/**
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* Divide one number by another.
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* @param env the evaluation environment - ignored;
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* @param frame the stack frame.
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* @return a pointer to an integer or real.
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*/
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struct cons_pointer lisp_divide( struct
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stack_frame
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*frame, struct cons_pointer frame_pointer, struct
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cons_pointer env ) {
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struct cons_pointer result = NIL;
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struct cons_space_object arg0 = pointer2cell( frame->arg[0] );
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struct cons_space_object arg1 = pointer2cell( frame->arg[1] );
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switch ( arg0.tag.value ) {
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case EXCEPTIONTV:
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result = frame->arg[0];
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break;
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case INTEGERTV:
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switch ( arg1.tag.value ) {
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case EXCEPTIONTV:
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result = frame->arg[1];
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break;
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case INTEGERTV:{
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struct cons_pointer unsimplified =
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make_ratio( frame_pointer, frame->arg[0],
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frame->arg[1] );
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/* OK, if result may be unsimplified, we should not inc_ref it
|
|
* - but if not, we should dec_ref it. */
|
|
result = simplify_ratio( frame_pointer, unsimplified );
|
|
if ( !eq( unsimplified, result ) ) {
|
|
dec_ref( unsimplified );
|
|
}
|
|
}
|
|
break;
|
|
case RATIOTV:{
|
|
struct cons_pointer one = make_integer( 1 );
|
|
struct cons_pointer ratio =
|
|
make_ratio( frame_pointer, frame->arg[0], one );
|
|
result =
|
|
divide_ratio_ratio( frame_pointer, ratio,
|
|
frame->arg[1] );
|
|
dec_ref( ratio );
|
|
}
|
|
break;
|
|
case REALTV:
|
|
result =
|
|
make_real( to_long_double( frame->arg[0] ) /
|
|
to_long_double( frame->arg[1] ) );
|
|
break;
|
|
default:
|
|
result = throw_exception( c_string_to_lisp_string
|
|
( L"Cannot divide: not a number" ),
|
|
frame_pointer );
|
|
break;
|
|
}
|
|
break;
|
|
case RATIOTV:
|
|
switch ( arg1.tag.value ) {
|
|
case EXCEPTIONTV:
|
|
result = frame->arg[1];
|
|
break;
|
|
case INTEGERTV:{
|
|
struct cons_pointer one = make_integer( 1 );
|
|
inc_ref( one );
|
|
struct cons_pointer ratio =
|
|
make_ratio( frame_pointer, frame->arg[1], one );
|
|
inc_ref( ratio );
|
|
result =
|
|
divide_ratio_ratio( frame_pointer, frame->arg[0],
|
|
ratio );
|
|
dec_ref( ratio );
|
|
dec_ref( one );
|
|
}
|
|
break;
|
|
case RATIOTV:
|
|
result =
|
|
divide_ratio_ratio( frame_pointer, frame->arg[0],
|
|
frame->arg[1] );
|
|
break;
|
|
case REALTV:
|
|
result =
|
|
make_real( to_long_double( frame->arg[0] ) /
|
|
to_long_double( frame->arg[1] ) );
|
|
break;
|
|
default:
|
|
result = throw_exception( c_string_to_lisp_string
|
|
( L"Cannot divide: not a number" ),
|
|
frame_pointer );
|
|
break;
|
|
}
|
|
break;
|
|
case REALTV:
|
|
result = exceptionp( frame->arg[1] ) ? frame->arg[1] :
|
|
make_real( to_long_double( frame->arg[0] ) /
|
|
to_long_double( frame->arg[1] ) );
|
|
break;
|
|
default:
|
|
result = throw_exception( c_string_to_lisp_string
|
|
( L"Cannot divide: not a number" ),
|
|
frame_pointer );
|
|
break;
|
|
}
|
|
|
|
return result;
|
|
}
|