include term-colours.4th
include defer-is.4th
+include goto.4th
include catch-throw.4th
include integer.4th
include float.4th
defer read
defer expand
+defer analyze
defer eval
defer print
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 ---- {{{
2swap
;
-: apply ( proc argvals -- result )
- 2swap dup case
- primitive-proc-type of
- drop execute
- endof
+\ }}}
+
+\ ---- Analyze ----
+
+: evaluate-eproc ( eproc env --- res )
+
+ >R >R
+
+ begin
+ nil? invert
+ while
+ 2dup car
+ 2swap cdr
+ repeat
+
+ 2drop \ get rid of null
+
+ R> R> 2swap
+
+ \ 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
- compound-proc-type of
+ 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? if
+ 2swap 2drop
+ else
+ 2over 2over car 2swap evaluate-eproc ( env aprocs thisval )
+ -2rot cdr recurse ( thisval restvals )
+ cons
+ then
+;
+
+: application-executor ( operator-proc arg-procs env -- res )
+ 2rot 2over ( aprocs env fproc env )
+ evaluate-eproc ( aprocs env proc )
+
+ -2rot 2swap ( proc env aprocs )
+ evaluate-operand-eprocs ( proc vals )
+
+ 2swap ( vals proc )
+
+ dup case
+ primitive-proc-type of
+ drop execute
+ endof
+
+ compound-proc-type of
2dup procedure-body ( argvals proc body )
- -2rot 2dup procedure-params ( body argvals proc argnames )
- -2rot procedure-env ( body argnames argvals procenv )
+ -2rot 2dup procedure-params ( bproc argvals proc argnames )
+ -2rot procedure-env ( bproc argnames argvals procenv )
-2rot 2swap
flatten-proc-args
2swap 2rot
- extend-env ( body env )
-
- eval-sequence
+ extend-env ( bproc env )
- R> drop ['] eval goto-deferred \ Tail call optimization
- endof
+ ['] evaluate-eproc goto
+ endof
- except-message: ." object '" drop print ." ' not applicable." recoverable-exception throw
- endcase
+ except-message: ." object '" drop print ." ' not applicable." recoverable-exception throw
+ endcase
;
-:noname ( obj env -- result )
- 2swap
+: analyze-application ( exp -- eproc )
+ 2dup operator analyze
+ 2swap operands operand-eproc-list
+
+ ['] application-executor primitive-proc-type
+ nil cons cons cons
+;
- \ --- DEBUG ---
- (
- fg yellow ." Evaluating: " bold 2dup print reset-term
- space fg green ." PS: " bold depth . reset-term
- space fg blue ." RS: " bold RSP@ RSP0 - . reset-term cr
- )
+:noname ( exp --- eproc )
self-evaluating? if
- 2swap 2drop
+ analyze-self-evaluating
exit
then
quote? if
- quote-body
- 2swap 2drop
+ analyze-quoted
exit
then
-
+
variable? if
- 2swap lookup-var
+ analyze-variable
exit
then
definition? if
- 2swap eval-definition
+ analyze-definition
exit
then
- assignment? if
- 2swap eval-assignment
- exit
- then
+\ macro-definition? if
+\ analyze-macro-definition
+\ exit
+\ then
- macro-definition? if
- 2swap eval-define-macro
+ assignment? if
+ analyze-assignment
exit
then
if? if
- 2over 2over
- if-predicate
- 2swap eval
-
- true? if
- if-consequent
- else
- if-alternative
- then
-
- 2swap
- ['] eval goto-deferred
+ analyze-if
+ exit
then
lambda? if
- 2dup lambda-parameters
- 2swap lambda-body
- 2rot make-procedure
+ analyze-lambda
exit
then
application? if
-
- 2over 2over ( env exp env exp )
- operator ( env exp env opname )
-
- 2swap eval ( env exp proc )
-
- -2rot ( proc env exp )
- operands 2swap ( proc operands env )
- list-of-vals ( proc argvals )
-
- apply
+ analyze-application
exit
then
- except-message: ." tried to evaluate object with unknown type." recoverable-exception throw
-; is eval
+
+ except-message: ." tried to analyze unknown expression type." recoverable-exception throw
+
+; is analyze
-\ }}}
\ ---- Macro Expansion ---- {{{
\ }}}
+:noname ( exp env -- res )
+ 2swap expand analyze 2swap evaluate-eproc
+; is eval
+
\ ---- Print ---- {{{
: printfixnum ( fixnum -- ) drop 0 .R ;
2swap 2drop ( port obj )
- expand
-
global-env obj@ eval ( port res )
again
;
include scheme-primitives.4th
- s" testing-library.scm" load 2drop
\ s" scheme-library.scm" load 2drop
\ }}}
true exit
then
- expand
-
global-env obj@ eval
fg cyan ." ; " print reset-term
enable-gc
\ Display welcome message
- welcome-symbol nil cons global-env obj@ eval 2drop
+ \ welcome-symbol nil cons global-env obj@ eval 2drop
begin
['] repl-body catch