From ce1c72973db7b80b381333b9daa60f6f288b8c28 Mon Sep 17 00:00:00 2001
From: Simon Brooke <simon@journeyman.cc>
Date: Thu, 13 Mar 2025 12:47:54 +0000
Subject: [PATCH] Defensive commit before experimenting with code::blocks

---
 src/arith/peano.h |  4 ++++
 src/io/read.c     | 19 ++++++++++---------
 src/io/read.h     |  9 +++++++++
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/src/arith/peano.h b/src/arith/peano.h
index 3076391..b1d3087 100644
--- a/src/arith/peano.h
+++ b/src/arith/peano.h
@@ -14,6 +14,10 @@
 
 /**
  * The maximum value we will allow in an integer cell.
+ *
+ * NOTE: 20250312 this is 2^60. WHY? Given that we're using the sign bit
+ * inside the int64 record, we only have 63 value bits; but why did I decide
+ * not to use all 63?
  */
 #define MAX_INTEGER ((__int128_t)0x0fffffffffffffffL)
 
diff --git a/src/io/read.c b/src/io/read.c
index df0735b..bf92f35 100644
--- a/src/io/read.c
+++ b/src/io/read.c
@@ -83,7 +83,7 @@ struct cons_pointer read_path( URL_FILE * input, wint_t initial,
             prefix = c_string_to_lisp_symbol( L"oblist" );
             break;
         case '$':
-        case L'§':
+        case LSESSION:
             prefix = c_string_to_lisp_symbol( L"session" );
             break;
     }
@@ -245,7 +245,7 @@ struct cons_pointer read_continuation( struct stack_frame *frame,
                 }
                 break;
             case '$':
-            case L'§':
+            case LSESSION:
                 result = read_path( input, c, NIL );
                 break;
             default:
@@ -298,9 +298,9 @@ struct cons_pointer read_number( struct stack_frame *frame,
                   initial );
 
     for ( c = initial; iswdigit( c )
-          || c == L'.' || c == L'/' || c == L','; c = url_fgetwc( input ) ) {
+          || c == LPERIOD || c == LSLASH || c == LCOMMA; c = url_fgetwc( input ) ) {
         switch ( c ) {
-            case L'.':
+            case LPERIOD:
                 if ( seen_period || !nilp( dividend ) ) {
                     return throw_exception( c_string_to_lisp_string
                                             ( L"Malformed number: too many periods" ),
@@ -311,7 +311,7 @@ struct cons_pointer read_number( struct stack_frame *frame,
                     seen_period = true;
                 }
                 break;
-            case L'/':
+            case LSLASH:
                 if ( seen_period || !nilp( dividend ) ) {
                     return throw_exception( c_string_to_lisp_string
                                             ( L"Malformed number: dividend of rational must be integer" ),
@@ -324,11 +324,12 @@ struct cons_pointer read_number( struct stack_frame *frame,
                     result = make_integer( 0, NIL );
                 }
                 break;
-            case L',':
+            case LCOMMA:
                 // silently ignore it.
                 break;
             default:
                 result = add_integers( multiply_integers( result, base ),
+                                        /* /todo: this won't work for hex digits */
                                        make_integer( ( int ) c - ( int ) '0',
                                                      NIL ) );
 
@@ -402,7 +403,7 @@ struct cons_pointer read_list( struct stack_frame *frame,
         for ( c = url_fgetwc( input );
               iswblank( c ) || iswcntrl( c ); c = url_fgetwc( input ) );
 
-        if ( c == L'.' ) {
+        if ( c == LPERIOD ) {
             /* might be a dotted pair; indeed, if we rule out numbers with
              * initial periods, it must be a dotted pair. \todo Ought to check,
              * howerver, that there's only one form after the period. */
@@ -433,7 +434,7 @@ struct cons_pointer read_map( struct stack_frame *frame,
         make_hashmap( DFLT_HASHMAP_BUCKETS, NIL, TRUE );
     wint_t c = initial;
 
-    while ( c != L'}' ) {
+    while ( c != LCBRACE ) {
         struct cons_pointer key =
             read_continuation( frame, frame_pointer, env, input, c );
 
@@ -446,7 +447,7 @@ struct cons_pointer read_map( struct stack_frame *frame,
 
         /* skip commaa and whitespace at this point. */
         for ( c = url_fgetwc( input );
-              c == L',' || iswblank( c ) || iswcntrl( c );
+              c == LCOMMA || iswblank( c ) || iswcntrl( c );
               c = url_fgetwc( input ) );
 
         result =
diff --git a/src/io/read.h b/src/io/read.h
index 031bb4f..7f58d0c 100644
--- a/src/io/read.h
+++ b/src/io/read.h
@@ -13,6 +13,15 @@
 
 #include "memory/consspaceobject.h"
 
+/* characters (other than arabic numberals) used in number representations */
+#define LCOMMA L','
+#define LPERIOD L'.'
+#define LSLASH L'/'
+/* ... used in map representations */
+#define LCBRACE L'}'
+/* ... used in path representations */
+#define LSESSION L'§'
+
 /**
  * read the next object on this input stream and return a cons_pointer to it.
  */