X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=scheme.4th;h=89b316011ffb5a1b318ae46396f7f9075905e401;hb=1e77138f35f12ccc6fe20d943482ac6b57c3f7cd;hp=8bc44d3ad9693c76273660e20f42cac8b5ac9941;hpb=215a272cf2521c34e9f8d2be62db1a35ac0a9809;p=scheme.forth.jl.git

diff --git a/scheme.4th b/scheme.4th
index 8bc44d3..89b3160 100644
--- a/scheme.4th
+++ b/scheme.4th
@@ -3,23 +3,35 @@ scheme definitions
 
 include term-colours.4th
 include defer-is.4th
-include catch-throw.4th
+include float.4th
+
+include debugging.4th
 
 defer read
 defer eval
 defer print
 
+defer collect-garbage
+
 \ ------ Types ------
 
-0 constant fixnum-type
-1 constant boolean-type
-2 constant character-type
-3 constant string-type
-4 constant nil-type
-5 constant pair-type
-6 constant symbol-type
-7 constant primitive-proc-type
-8 constant compound-proc-type
+variable nexttype
+0 nexttype !
+: make-type
+    create nexttype @ ,
+    1 nexttype +!
+    does> @ ;
+
+make-type fixnum-type
+make-type realnum-type
+make-type boolean-type
+make-type character-type
+make-type string-type
+make-type nil-type
+make-type pair-type
+make-type symbol-type
+make-type primitive-proc-type
+make-type compound-proc-type
 : istype? ( obj type -- obj bool )
     over = ;
 
@@ -43,6 +55,8 @@ variable nextfree
     nextfree @ pair-type
 
     1 nextfree +!
+
+    collect-garbage
 ;
 
 : car ( pair-obj -- car-obj )
@@ -105,6 +119,28 @@ variable nextfree
 
 \ }}}
 
+\ ---- Garbage Collection ---- {{{
+
+variable gc-enabled
+false gc-enabled !
+
+: gc-enable
+    true gc-enabled ! ;
+
+: gc-disable
+    false gc-enabled ! ;
+
+: gc-enabled?
+    gc-enabled @ ;
+
+:noname 
+    gc-enabled? if
+        .s ." GC!" cr
+    then
+; is collect-garbage
+
+\ }}}
+
 \ ---- Pre-defined symbols ---- {{{
 
 objvar symbol-table
@@ -332,6 +368,8 @@ global-env obj!
     bl word
     count
 
+    \ 2dup ." Defining primitive " type ." ..." cr
+
     (create-symbol)
     drop symbol-type
     
@@ -500,13 +538,52 @@ parse-idx-stack parse-idx-sp !
         inc-parse-idx
     repeat
 
-    delim? if
-        pop-parse-idx
-        true
-    else
-        pop-parse-idx
-        false
+    delim? pop-parse-idx
+;
+
+: realnum? ( -- bool )
+    push-parse-idx
+
+    minus? plus? or if
+        inc-parse-idx
+    then
+
+    \ Record starting parse idx:
+    \ Want to detect whether any characters (following +/-) were eaten.
+    parse-idx @
+
+    begin digit? while
+            inc-parse-idx
+    repeat
+
+    [char] . nextchar = if
+        inc-parse-idx
+        begin digit? while
+                inc-parse-idx
+        repeat
     then
+
+    [char] e nextchar = [char] E nextchar = or if
+        inc-parse-idx
+
+        minus? plus? or if
+            inc-parse-idx
+        then
+
+        digit? invert if
+            drop pop-parse-idx false exit
+        then
+
+        begin digit? while
+                inc-parse-idx
+        repeat
+    then
+
+    \ This is a real number if characters were
+    \ eaten and the next characer is a delimiter.
+    parse-idx @ < delim? and
+
+    pop-parse-idx
 ;
 
 : boolean? ( -- bool )
@@ -576,7 +653,7 @@ parse-idx-stack parse-idx-sp !
 : string? ( -- bool )
     nextchar [char] " = ;
 
-: readnum ( -- num-atom )
+: readfixnum ( -- num-atom )
     plus? minus? or if
         minus?
         inc-parse-idx
@@ -596,6 +673,24 @@ parse-idx-stack parse-idx-sp !
     fixnum-type
 ;
 
+: readrealnum ( -- realnum )
+
+    \ Remember that at this point we're guaranteed to
+    \ have a parsable real on this line.
+
+    parse-str parse-idx @ +
+
+    begin delim? false = while
+            inc-parse-idx
+    repeat
+
+    parse-str parse-idx @ + over -
+
+    float-parse
+
+    realnum-type
+;
+
 : readbool ( -- bool-atom )
     inc-parse-idx
     
@@ -713,7 +808,12 @@ parse-idx-stack parse-idx-sp !
     eatspaces
 
     fixnum? if
-        readnum
+        readfixnum
+        exit
+    then
+
+    realnum? if
+        readrealnum
         exit
     then
 
@@ -769,7 +869,7 @@ parse-idx-stack parse-idx-sp !
 
     eof? if
         inc-parse-idx
-        bold fg blue ." Moriturus te saluto." reset-term ."  ok" cr
+        bold fg blue ." Moriturus te saluto." reset-term cr
         quit
     then
 
@@ -791,6 +891,7 @@ parse-idx-stack parse-idx-sp !
 : self-evaluating? ( obj -- obj bool )
     boolean-type istype? if true exit then
     fixnum-type istype? if true exit then
+    realnum-type istype? if true exit then
     character-type istype? if true exit then
     string-type istype? if true exit then
     nil-type istype? if true exit then
@@ -1059,7 +1160,9 @@ parse-idx-stack parse-idx-sp !
 
 \ ---- Print ---- {{{
 
-: printnum ( numobj -- ) drop 0 .R ;
+: printfixnum ( fixnumobj -- ) drop 0 .R ;
+
+: printrealnum ( realnumobj -- ) drop float-print ;
 
 : printbool ( numobj -- )
     drop if
@@ -1124,7 +1227,8 @@ parse-idx-stack parse-idx-sp !
     2drop ." <compound procedure>" ;
 
 :noname ( obj -- )
-    fixnum-type istype? if printnum exit then
+    fixnum-type istype? if printfixnum exit then
+    realnum-type istype? if printrealnum exit then
     boolean-type istype? if printbool exit then
     character-type istype? if printchar exit then
     string-type istype? if printstring exit then
@@ -1146,12 +1250,17 @@ parse-idx-stack parse-idx-sp !
     cr ." Welcome to scheme.forth.jl!" cr
        ." Use Ctrl-D to exit." cr
 
+    
     empty-parse-str
 
+    gc-enable
+
     begin
         cr bold fg green ." > " reset-term
         read
+
         global-env obj@ eval
+
         fg cyan ." ; " print reset-term
     again
 ;