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Now successfully reading/printing 2 cell bignums

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Something is wrong with n-cell bignums, but let's make haste slowly.
This commit is contained in:
Simon Brooke 2019-01-04 10:39:48 +00:00
parent d9d789fdd0
commit 67802a07b8
5 changed files with 192 additions and 174 deletions
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66
src/ops/read.c
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@ -23,6 +23,7 @@
#include "integer.h"
#include "intern.h"
#include "lispops.h"
#include "peano.h"
#include "print.h"
#include "ratio.h"
#include "read.h"
@ -152,25 +153,25 @@ struct cons_pointer read_continuation( struct stack_frame *frame,
/**
* read a number from this input stream, given this initial character.
* TODO: to be able to read bignums, we need to read the number from the
* input stream into a Lisp string, and then convert it to a number.
* TODO: Need to do a lot of inc_ref and dec_ref, to make sure the
* garbage is collected.
*/
struct cons_pointer read_number( struct stack_frame *frame,
struct cons_pointer frame_pointer,
FILE * input,
wint_t initial, bool seen_period ) {
debug_print( L"entering read_number\n", DEBUG_IO );
struct cons_pointer result = NIL;
/* TODO: accumulator and dividend cannot be `int64_t`s, otherwise we cannot
* read bignums. They will have to be Lisp integers. */
int64_t accumulator = 0;
int64_t dividend = 0;
struct cons_pointer result = make_integer( 0, NIL );
/* TODO: we really need to be getting `base` from a privileged Lisp name -
* and it should be the same privileged name we use when writing numbers */
struct cons_pointer base = make_integer( 10, NIL );
struct cons_pointer dividend = NIL;
int places_of_decimals = 0;
wint_t c;
bool negative = initial == btowc( '-' );
bool neg = initial == btowc( '-' );
if ( negative ) {
if ( neg ) {
initial = fgetwc( input );
}
@ -180,7 +181,7 @@ struct cons_pointer read_number( struct stack_frame *frame,
for ( c = initial; iswdigit( c )
|| c == L'.' || c == L'/' || c == L','; c = fgetwc( input ) ) {
if ( c == btowc( '.' ) ) {
if ( seen_period || dividend != 0 ) {
if ( seen_period || !nilp( dividend ) ) {
return throw_exception( c_string_to_lisp_string
( L"Malformed number: too many periods" ),
frame_pointer );
@ -188,23 +189,24 @@ struct cons_pointer read_number( struct stack_frame *frame,
seen_period = true;
}
} else if ( c == btowc( '/' ) ) {
if ( seen_period || dividend > 0 ) {
if ( seen_period || !nilp( dividend ) ) {
return throw_exception( c_string_to_lisp_string
( L"Malformed number: dividend of rational must be integer" ),
frame_pointer );
} else {
dividend = negative ? 0 - accumulator : accumulator;
dividend = result;
accumulator = 0;
result = make_integer( 0, NIL );
}
} else if ( c == L',' ) {
// silently ignore it.
} else {
accumulator = accumulator * 10 + ( ( int ) c - ( int ) '0' );
result = add_integers( multiply_integers( result, base ),
make_integer( ( int ) c - ( int ) '0',
NIL ) );
debug_printf( DEBUG_IO,
L"Added character %c, accumulator now %ld\n",
c, accumulator );
L"Added character %c, result now %ld\n", c, result );
if ( seen_period ) {
places_of_decimals++;
@ -217,21 +219,23 @@ struct cons_pointer read_number( struct stack_frame *frame,
*/
ungetwc( c, input );
if ( seen_period ) {
long double rv = ( long double )
( accumulator / pow( 10, places_of_decimals ) );
if ( negative ) {
rv = 0 - rv;
}
result = make_real( rv );
} else if ( dividend != 0 ) {
result =
make_ratio( frame_pointer, make_integer( dividend, NIL ),
make_integer( accumulator, NIL ) );
} else {
if ( negative ) {
accumulator = 0 - accumulator;
}
result = make_integer( accumulator, NIL );
struct cons_pointer div = make_ratio( frame_pointer, result,
make_integer( powl
( to_long_double
( base ),
places_of_decimals ),
NIL ) );
inc_ref( div );
result = make_real( to_long_double( div ) );
dec_ref( div );
} else if ( integerp( dividend ) ) {
result = make_ratio( frame_pointer, dividend, result );
}
if ( neg ) {
result = negative( frame_pointer, result );
}
debug_print( L"read_number returning\n", DEBUG_IO );