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mal/factor/step7_quote/step7_quote.factor
Nicolas Boulenguez e6d41de4d5 load-file: accept empty file or final comment, return nil
Let `load-file` append a new line in case last line contains a
comment.

Also append `nil` so that the return value is predictible. Remove the
existing explicit `nil` from existing sources.

Adapt documentation and tests.
2019-07-28 13:08:05 +02:00

128 lines
3.6 KiB
Factor
Executable File

! Copyright (C) 2015 Jordan Lewis.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors arrays assocs combinators
combinators.short-circuit command-line continuations fry
grouping hashtables io kernel lists locals lib.core lib.env
lib.printer lib.reader lib.types math namespaces quotations
readline sequences splitting ;
IN: step7_quote
SYMBOL: repl-env
DEFER: EVAL
: eval-ast ( ast env -- ast )
{
{ [ over malsymbol? ] [ env-get ] }
{ [ over sequence? ] [ '[ _ EVAL ] map ] }
{ [ over assoc? ] [ '[ [ _ EVAL ] bi@ ] assoc-map ] }
[ drop ]
} cond ;
:: eval-def! ( key value env -- maltype )
value env EVAL [ key env env-set ] keep ;
: eval-let* ( bindings body env -- maltype env )
[ swap 2 group ] [ new-env ] bi* [
dup '[ first2 _ EVAL swap _ env-set ] each
] keep ;
:: eval-do ( exprs env -- lastform env/f )
exprs [
{ } f
] [
unclip-last [ env eval-ast drop ] dip env
] if-empty ;
:: eval-if ( params env -- maltype env/f )
params first env EVAL { f +nil+ } index not [
params second env
] [
params length 2 > [ params third env ] [ nil f ] if
] if ;
:: eval-fn* ( params env -- maltype )
env params first [ name>> ] map params second <malfn> ;
: args-split ( bindlist -- bindlist restbinding/f )
{ "&" } split1 ?first ;
: make-bindings ( args bindlist restbinding/f -- bindingshash )
swapd [ over length cut [ zip ] dip ] dip
[ swap 2array suffix ] [ drop ] if* >hashtable ;
GENERIC: apply ( args fn -- maltype newenv/f )
M: malfn apply
[ exprs>> nip ]
[ env>> nip ]
[ binds>> args-split make-bindings ] 2tri <malenv> ;
M: callable apply call( x -- y ) f ;
: is-pair? ( maltype -- bool )
{ [ sequence? ] [ empty? not ] } 1&& ;
: quasiquote ( maltype -- maltype )
{
{ [ dup is-pair? not ] [ [ "quote" <malsymbol> ] dip 2array ] }
{ [ "unquote" over first symeq? ] [ second ] }
{ [ dup first { [ is-pair? ] [ first "splice-unquote" swap symeq? ] } 1&& ]
[ [ "concat" <malsymbol> ] dip unclip second swap quasiquote 3array ] }
[ "cons" <malsymbol> swap unclip quasiquote swap quasiquote 3array ]
} cond ;
: READ ( str -- maltype ) read-str ;
: EVAL ( maltype env -- maltype )
over { [ array? ] [ empty? not ] } 1&& [
over first dup malsymbol? [ name>> ] when {
{ "def!" [ [ rest first2 ] dip eval-def! f ] }
{ "let*" [ [ first2 ] dip eval-let* ] }
{ "do" [ [ rest ] dip eval-do ] }
{ "if" [ [ rest ] dip eval-if ] }
{ "fn*" [ [ rest ] dip eval-fn* f ] }
{ "quote" [ drop second f ] }
{ "quasiquote" [ [ second quasiquote ] dip ] }
[ drop '[ _ EVAL ] map unclip apply ]
} case [ EVAL ] when*
] [
eval-ast
] if ;
[ apply [ EVAL ] when* ] mal-apply set-global
: PRINT ( maltype -- str ) pr-str ;
: REP ( str -- str )
[
READ repl-env get EVAL PRINT
] [
nip pr-str "Error: " swap append
] recover ;
: REPL ( -- )
[
"user> " readline [
[ REP print flush ] unless-empty
] keep
] loop ;
: main ( -- )
command-line get
[ REPL ]
[ first "(load-file \"" "\")" surround REP drop ]
if-empty ;
f ns clone
[ first repl-env get EVAL ] "eval" pick set-at
command-line get dup empty? [ rest ] unless "*ARGV*" pick set-at
<malenv> repl-env set-global
"
(def! not (fn* (a) (if a false true)))
(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \"\\nnil)\")))))
" string-lines harvest [ REP drop ] each
MAIN: main