X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=src%2Fscheme.4th;h=7a1a1dc331d67013b87ee43e222fe0e789ba395e;hb=4c218f83d186381b93631feba95b27ddb6fe24a3;hp=0722208250945ab9165d8d6b1c410711ee65cdc8;hpb=f1bd626bdb02170b189891d8f8f3f3cc6b592209;p=scheme.forth.jl.git

diff --git a/src/scheme.4th b/src/scheme.4th
index 0722208..7a1a1dc 100644
--- a/src/scheme.4th
+++ b/src/scheme.4th
@@ -3,6 +3,7 @@ scheme definitions
 
 include term-colours.4th
 include defer-is.4th
+include goto.4th
 include catch-throw.4th
 include integer.4th
 include float.4th
@@ -10,6 +11,8 @@ include float.4th
 include debugging.4th
 
 defer read
+defer expand
+defer analyze
 defer eval
 defer print
 
@@ -161,6 +164,10 @@ variable nextfree
     R> R>
 ;
 
+: 2pick ( an bn an-1 bn-1 ... a0 b0 n -- an bn an-1 bn-1 ... a0 b0 an bn )
+    2* 1+ dup
+    >R pick R> pick ;
+
 \ }}}
 
 \ ---- Pre-defined symbols ---- {{{
@@ -261,7 +268,6 @@ create-symbol ok                ok-symbol
 create-symbol if                if-symbol
 create-symbol lambda            lambda-symbol
 create-symbol λ                 λ-symbol
-create-symbol begin             begin-symbol
 create-symbol eof               eof-symbol
 create-symbol no-match          no-match-symbol
 
@@ -1512,12 +1518,6 @@ hide env
 : lambda-body ( obj -- body )
     cdr cdr ;
 
-: begin? ( obj -- obj bool )
-    begin-symbol tagged-list? ;
-
-: begin-actions ( obj -- actions )
-    cdr ;
-
 : eval-sequence ( explist env -- finalexp env )
     ( Evaluates all bar the final expressions in
       an an expression list. The final expression
@@ -1712,12 +1712,6 @@ hide env
         exit
     then
 
-    begin? if
-        begin-actions 2swap
-        eval-sequence
-        ['] eval goto-deferred
-    then
-
     application? if
 
         2over 2over ( env exp env exp )
@@ -1738,6 +1732,254 @@ hide env
 
 \ }}}
 
+\ ---- Analyze ----
+
+: evaluate-eproc ( eproc env --- res )
+
+    >R >R
+    
+    begin
+        nil? invert
+    while
+        2dup car
+        2swap cdr
+    repeat
+    
+    2drop \ get rid of null
+
+    R> R>
+
+    \ Final element of eproc list is primitive procedure
+    drop \ dump type signifier
+    goto \ jump straight to primitive procedure (executor)
+;
+
+: self-evaluating-executor ( exp env -- exp )
+    2drop ;
+
+: analyze-self-evaluating ( exp --- eproc )
+    ['] self-evaluating-executor primitive-proc-type
+    nil cons cons
+;
+
+: quote-executor ( exp env -- exp )
+    2drop ;
+
+: analyze-quoted ( exp -- eproc )
+    quote-body
+
+    ['] quote-executor primitive-proc-type
+    nil cons cons
+;
+
+: variable-executor ( var env -- val )
+    lookup-var ;
+
+: analyze-variable ( exp -- eproc )
+    ['] variable-executor primitive-proc-type
+    nil cons cons
+;
+
+: definition-executor ( var val-eproc env -- ok )
+    2swap 2over ( var env val-eproc env )
+    evaluate-eproc 2swap ( var val env )
+    define-var
+    ok-symbol
+;
+
+: analyze-definition ( exp -- eproc )
+    2dup definition-var
+    2swap definition-val analyze
+
+    ['] definition-executor primitive-proc-type
+    nil cons cons cons
+;
+
+: assignment-executor ( var val-eproc env -- ok )
+    2swap 2over ( var env val-eproc env )
+    evaluate-eproc 2swap ( var val env )
+    set-var
+    ok-symbol
+;
+
+: analyze-assignment ( exp -- eproc )
+    2dup assignment-var
+    2swap assignment-val analyze ( var val-eproc )
+
+    ['] assignment-executor primitive-proc-type
+    nil cons cons cons
+;
+
+: if-executor ( cproc aproc pproc env -- res )
+    2swap 2over ( cproc aproc env pproc env -- res )
+    evaluate-eproc
+
+    true? if
+        2swap 2drop
+    else
+        2rot 2drop
+    then
+
+    evaluate-eproc
+;
+
+: analyze-if ( exp -- eproc )
+    2dup if-predicate analyze
+    2swap 2dup if-consequent analyze
+    2swap if-alternative analyze
+
+    ['] if-executor primitive-proc-type
+    nil cons cons cons cons
+;
+
+: sequence-executor ( eproc-list env -- res )
+    2swap
+
+    begin
+        2dup cdr ( env elist elist-rest)
+        nil? invert
+    while
+
+        -2rot car 2over ( elist-rest env elist-head env )
+        evaluate-eproc  ( elist-rest env head-res )
+        2drop 2swap     ( env elist-rest )
+    repeat
+
+    2drop car 2swap
+    ['] evaluate-eproc goto
+;
+
+
+: (analyze-sequence) ( explist -- eproc-list )
+    nil? if exit then
+
+    2dup car analyze
+    2swap cdr recurse
+
+    cons
+;
+
+: analyze-sequence ( explist -- eproc )
+    (analyze-sequence)
+    ['] sequence-executor primitive-proc-type
+    nil cons cons
+;
+
+: lambda-executor ( params bproc env -- res )
+    make-procedure
+    ( Although this is packaged up as a regular compound procedure,
+      the "body" element contains an _eproc_ to be evaluated in an
+      environment resulting from extending env with the parameter
+      bindings. )
+;
+
+: analyze-lambda ( exp -- eproc )
+    2dup lambda-parameters
+    2swap lambda-body
+
+    nil? if
+        except-message: ." encountered lambda with an empty body." recoverable-exception throw
+    then
+
+    analyze-sequence
+
+    ['] lambda-executor primitive-proc-type
+    nil cons cons cons
+;
+
+: operand-eproc-list ( operands -- eprocs )
+    nil? invert if
+        2dup car analyze
+        2swap cdr recurse
+        cons
+    then
+;
+
+: evaluate-operand-eprocs ( env aprocs -- vals )
+    nil? invert if
+        2over 2over car evaluate-eproc ( env aprocs thisres )
+        -rot cdr recurse
+;
+
+: application-executor ( operator-proc arg-procs env -- res )
+    2rot 2over ( aprocs env fproc env )
+    evaluate-eproc ( aprocs env proc )
+    2swap -2rot 2over 2swap ( proc env env aprocs )
+    evaluate-operand-eprocs ( proc env vals )
+    
+    2rot ( env vals proc )
+    
+    dup case
+        primitive-proc-type of
+            2rot 2drop execute
+        endof
+
+        compound-proc-type of
+                2dup procedure-body ( argvals proc body )
+                -2rot 2dup procedure-params ( bproc argvals proc argnames )
+                -2rot procedure-env ( bproc argnames argvals procenv )
+
+                -2rot 2swap
+                flatten-proc-args
+                2swap 2rot
+
+                extend-env ( bproc env )
+
+               ['] evaluate-eproc goto
+        endof
+
+        except-message: ." object '" drop print ." ' not applicable." recoverable-exception throw
+    endcase
+;
+
+: analyze-application ( exp -- eproc )
+    2dup operator analyze
+    2swap operands operand-eproc-list
+
+    ['] application-executor
+    nil cons cons cons
+;
+
+:noname ( exp --- eproc )
+
+    self-evaluating? if
+        analyze-self-evaluating
+        exit
+    then
+
+    quote? if
+        analyze-quoted
+        exit
+    then
+    
+    variable? if
+        analyze-variable
+        exit
+    then
+
+    definition? if
+        analyze-definition
+        exit
+    then
+
+    assignment? if
+        analyze-assignment
+        exit
+    then
+
+    if? if
+        analyze-if
+        exit
+    then
+
+    lambda? if
+        analyze-lambda
+        exit
+    then
+
+; is analyze
+
+
 \ ---- Macro Expansion ---- {{{
 
 ( Simply evaluates the given procedure with expbody as its argument. )
@@ -1754,14 +1996,6 @@ hide env
     extend-env eval-sequence eval
 ;
 
-defer expand
-
-: expand-quasiquote ;
-: expand-define-macro ;
-: expand-if ;
-: expand-lambda ;
-: expand-application ;
-
 : expand-macro ( exp -- result )
     pair-type istype? invert if exit then
     2dup car symbol-type istype? invert if 2drop exit then
@@ -1780,6 +2014,33 @@ defer expand
     R> drop ['] expand goto-deferred
 ;
 
+: expand-quasiquote-item ( exp -- result )
+    nil? if exit then
+
+    unquote? if
+        unquote-symbol 2swap cdr car expand nil cons cons
+        exit
+    then
+
+    unquote-splicing? if
+        unquote-splicing-symbol 2swap cdr car expand nil cons cons
+        exit
+    then
+    
+    pair-type istype? if
+        2dup car recurse
+        2swap cdr recurse
+        cons
+    then
+;
+
+: expand-quasiquote ( exp -- result )
+    quasiquote-symbol 2swap cdr
+
+    expand-quasiquote-item
+
+    cons ;
+
 : expand-definition ( exp -- result )
     define-symbol 2swap
 
@@ -1798,7 +2059,7 @@ defer expand
 
     cons cons cons ;
 
-: expand-sequence ( exp -- res )
+: expand-list ( exp -- res )
     nil? if exit then
 
     2dup car expand
@@ -1806,23 +2067,47 @@ defer expand
 
     cons ;
 
-: expand-begin ( exp -- res )
-    begin-symbol 2swap
-    begin-actions expand-sequence
+: macro-definition-nameparams
+    cdr car ;
+
+: expand-define-macro ( exp -- res )
+    define-macro-symbol 2swap
+    2dup macro-definition-nameparams
+    2swap macro-definition-body expand-list
 
-    cons ;
+    cons cons ;
 
 : expand-lambda ( exp -- res )
     lambda-symbol 2swap
     2dup lambda-parameters
-    2swap lambda-body expand-sequence
+    2swap lambda-body expand-list
 
     cons cons ;
 
-:noname ( exp -- result )
+: expand-if ( exp -- res )
+    if-symbol 2swap
+    
+    2dup if-predicate expand
+    2swap 2dup if-consequent expand
+    2swap if-alternative none? if
+        2drop nil
+    else
+        expand nil cons
+    then
 
+    cons cons cons ;
+
+: expand-application ( exp -- res )
+    2dup operator expand
+    2swap operands expand-list
+
+    cons ;
+
+:noname ( exp -- result )
     expand-macro
 
+    self-evaluating? if exit then
+
     quote? if exit then
 
     quasiquote? if expand-quasiquote exit then
@@ -1833,11 +2118,9 @@ defer expand
 
     macro-definition? if expand-define-macro exit then
 
-    if? if expand-if exit then
-
     lambda? if expand-lambda exit then
 
-    begin? if expand-begin exit then
+    if? if expand-if exit then
 
     application? if expand-application exit then
 
@@ -2081,9 +2364,7 @@ variable gc-stack-depth
 
     include scheme-primitives.4th
 
-    s" scheme-derived-forms.scm" load 2drop
-
-\    s" scheme-library.scm" load 2drop
+    \ s" scheme-library.scm" load 2drop
     
 \ }}}