ocaml/camlp4/meta/pa_rp.ml

319 lines
9.9 KiB
OCaml

(* camlp4r pa_extend.cmo q_MLast.cmo *)
(***********************************************************************)
(* *)
(* Camlp4 *)
(* *)
(* Daniel de Rauglaudre, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1998 Institut National de Recherche en Informatique et *)
(* Automatique. Distributed only by permission. *)
(* *)
(***********************************************************************)
(* $Id$ *)
open Pcaml;
type spat_comp =
[ SpTrm of MLast.loc and MLast.patt and option MLast.expr
| SpNtr of MLast.loc and MLast.patt and MLast.expr
| SpStr of MLast.loc and MLast.patt ]
;
type sexp_comp =
[ SeTrm of MLast.loc and MLast.expr | SeNtr of MLast.loc and MLast.expr ]
;
value strm_n = "strm__";
value peek_fun loc = <:expr< Stream.peek >>;
value junk_fun loc = <:expr< Stream.junk >>;
(* Parsers. *)
(* In syntax generated, many cases are optimisations. *)
value rec pattern_eq_expression p e =
match (p, e) with
[ (<:patt< $lid:a$ >>, <:expr< $lid:b$ >>) -> a = b
| (<:patt< $uid:a$ >>, <:expr< $uid:b$ >>) -> a = b
| (<:patt< $p1$ $p2$ >>, <:expr< $e1$ $e2$ >>) ->
pattern_eq_expression p1 e1 && pattern_eq_expression p2 e2
| _ -> False ]
;
value is_raise e =
match e with
[ <:expr< raise $_$ >> -> True
| _ -> False ]
;
value is_raise_failure e =
match e with
[ <:expr< raise Stream.Failure >> -> True
| _ -> False ]
;
value rec handle_failure e =
match e with
[ <:expr< try $te$ with [ Stream.Failure -> $e$] >> -> handle_failure e
| <:expr< match $me$ with [ $list:pel$ ] >> ->
handle_failure me &&
List.for_all
(fun
[ (_, None, e) -> handle_failure e
| _ -> False ])
pel
| <:expr< let $list:pel$ in $e$ >> ->
List.for_all (fun (p, e) -> handle_failure e) pel && handle_failure e
| <:expr< $lid:_$ >> | <:expr< $int:_$ >> | <:expr< $str:_$ >> |
<:expr< $chr:_$ >> | <:expr< fun [ $list:_$ ] >> | <:expr< $uid:_$ >> ->
True
| <:expr< raise $e$ >> ->
match e with
[ <:expr< Stream.Failure >> -> False
| _ -> True ]
| <:expr< $f$ $x$ >> ->
is_constr_apply f && handle_failure f && handle_failure x
| _ -> False ]
and is_constr_apply =
fun
[ <:expr< $uid:_$ >> -> True
| <:expr< $lid:_$ >> -> False
| <:expr< $x$ $_$ >> -> is_constr_apply x
| _ -> False ]
;
value rec subst v e =
let loc = MLast.loc_of_expr e in
match e with
[ <:expr< $lid:x$ >> ->
let x = if x = v then strm_n else x in <:expr< $lid:x$ >>
| <:expr< $uid:_$ >> -> e
| <:expr< $int:_$ >> -> e
| <:expr< $chr:_$ >> -> e
| <:expr< $str:_$ >> -> e
| <:expr< $_$.$_$ >> -> e
| <:expr< let $opt:rf$ $list:pel$ in $e$ >> ->
<:expr< let $opt:rf$ $list:List.map (subst_pe v) pel$ in $subst v e$ >>
| <:expr< $e1$ $e2$ >> -> <:expr< $subst v e1$ $subst v e2$ >>
| <:expr< ( $list:el$ ) >> -> <:expr< ( $list:List.map (subst v) el$ ) >>
| _ -> raise Not_found ]
and subst_pe v (p, e) =
match p with
[ <:patt< $lid:v'$ >> when v <> v' -> (p, subst v e)
| _ -> raise Not_found ]
;
value stream_pattern_component skont ckont =
fun
[ SpTrm loc p wo ->
<:expr< match $peek_fun loc$ $lid:strm_n$ with
[ Some $p$ $when:wo$ ->
do { $junk_fun loc$ $lid:strm_n$; $skont$ }
| _ -> $ckont$ ] >>
| SpNtr loc p e ->
let e =
match e with
[ <:expr< fun [ ($lid:v$ : Stream.t _) -> $e$ ] >> when v = strm_n -> e
| _ -> <:expr< $e$ $lid:strm_n$ >> ]
in
if pattern_eq_expression p skont then
if is_raise_failure ckont then e
else if handle_failure e then e
else <:expr< try $e$ with [ Stream.Failure -> $ckont$ ] >>
else if is_raise_failure ckont then <:expr< let $p$ = $e$ in $skont$ >>
else if pattern_eq_expression <:patt< Some $p$ >> skont then
<:expr< try Some $e$ with [ Stream.Failure -> $ckont$ ] >>
else if is_raise ckont then
let tst =
if handle_failure e then e
else <:expr< try $e$ with [ Stream.Failure -> $ckont$ ] >>
in
<:expr< let $p$ = $tst$ in $skont$ >>
else
<:expr< match try Some $e$ with [ Stream.Failure -> None ] with
[ Some $p$ -> $skont$
| _ -> $ckont$ ] >>
| SpStr loc p ->
try
match p with
[ <:patt< $lid:v$ >> -> subst v skont
| _ -> raise Not_found ]
with
[ Not_found -> <:expr< let $p$ = $lid:strm_n$ in $skont$ >> ] ]
;
value rec stream_pattern loc epo e ekont =
fun
[ [] ->
match epo with
[ Some ep -> <:expr< let $ep$ = Stream.count $lid:strm_n$ in $e$ >>
| _ -> e ]
| [(spc, err) :: spcl] ->
let skont =
let ekont err =
let str =
match err with
[ Some estr -> estr
| _ -> <:expr< "" >> ]
in
<:expr< raise (Stream.Error $str$) >>
in
stream_pattern loc epo e ekont spcl
in
let ckont = ekont err in stream_pattern_component skont ckont spc ]
;
value stream_patterns_term loc ekont tspel =
let pel =
List.map
(fun (p, w, loc, spcl, epo, e) ->
let p = <:patt< Some $p$ >> in
let e =
let ekont err =
let str =
match err with
[ Some estr -> estr
| _ -> <:expr< "" >> ]
in
<:expr< raise (Stream.Error $str$) >>
in
let skont = stream_pattern loc epo e ekont spcl in
<:expr< do { $junk_fun loc$ $lid:strm_n$; $skont$ } >>
in
(p, w, e))
tspel
in
let pel = pel @ [(<:patt< _ >>, None, ekont ())] in
<:expr< match $peek_fun loc$ $lid:strm_n$ with [ $list:pel$ ] >>
;
value rec group_terms =
fun
[ [([(SpTrm loc p w, None) :: spcl], epo, e) :: spel] ->
let (tspel, spel) = group_terms spel in
([(p, w, loc, spcl, epo, e) :: tspel], spel)
| spel -> ([], spel) ]
;
value rec parser_cases loc =
fun
[ [] -> <:expr< raise Stream.Failure >>
| spel ->
match group_terms spel with
[ ([], [(spcl, epo, e) :: spel]) ->
stream_pattern loc epo e (fun _ -> parser_cases loc spel) spcl
| (tspel, spel) ->
stream_patterns_term loc (fun _ -> parser_cases loc spel) tspel ] ]
;
value cparser loc bpo pc =
let e = parser_cases loc pc in
let e =
match bpo with
[ Some bp -> <:expr< let $bp$ = Stream.count $lid:strm_n$ in $e$ >>
| None -> e ]
in
let p = <:patt< ($lid:strm_n$ : Stream.t _) >> in <:expr< fun $p$ -> $e$ >>
;
value cparser_match loc me bpo pc =
let pc = parser_cases loc pc in
let e =
match bpo with
[ Some bp -> <:expr< let $bp$ = Stream.count $lid:strm_n$ in $pc$ >>
| None -> pc ]
in
match me with
[ <:expr< $lid:x$ >> when x = strm_n -> e
| _ -> <:expr< let ($lid:strm_n$ : Stream.t _) = $me$ in $e$ >> ]
;
(* streams *)
value rec not_computing =
fun
[ <:expr< $lid:_$ >> | <:expr< $uid:_$ >> | <:expr< $int:_$ >> |
<:expr< $flo:_$ >> | <:expr< $chr:_$ >> | <:expr< $str:_$ >> ->
True
| <:expr< $x$ $y$ >> -> is_cons_apply_not_computing x && not_computing y
| _ -> False ]
and is_cons_apply_not_computing =
fun
[ <:expr< $uid:_$ >> -> True
| <:expr< $lid:_$ >> -> False
| <:expr< $x$ $y$ >> -> is_cons_apply_not_computing x && not_computing y
| _ -> False ]
;
value slazy loc e =
match e with
[ <:expr< $f$ () >> ->
match f with
[ <:expr< $lid:_$ >> -> f
| _ -> <:expr< fun _ -> $e$ >> ]
| _ -> <:expr< fun _ -> $e$ >> ]
;
value rec cstream gloc =
fun
[ [] -> let loc = gloc in <:expr< Stream.sempty >>
| [SeTrm loc e] ->
if not_computing e then <:expr< Stream.ising $e$ >>
else <:expr< Stream.lsing $slazy loc e$ >>
| [SeTrm loc e :: secl] ->
if not_computing e then <:expr< Stream.icons $e$ $cstream gloc secl$ >>
else <:expr< Stream.lcons $slazy loc e$ $cstream gloc secl$ >>
| [SeNtr loc e] ->
if not_computing e then e else <:expr< Stream.slazy $slazy loc e$ >>
| [SeNtr loc e :: secl] ->
if not_computing e then <:expr< Stream.iapp $e$ $cstream gloc secl$ >>
else <:expr< Stream.lapp $slazy loc e$ $cstream gloc secl$ >> ]
;
(* Syntax extensions in Revised Syntax grammar *)
EXTEND
GLOBAL: expr;
expr: LEVEL "top"
[ [ "parser"; po = OPT ipatt; "["; pcl = LIST0 parser_case SEP "|"; "]" ->
<:expr< $cparser loc po pcl$ >>
| "parser"; po = OPT ipatt; pc = parser_case ->
<:expr< $cparser loc po [pc]$ >>
| "match"; e = SELF; "with"; "parser"; po = OPT ipatt; "[";
pcl = LIST0 parser_case SEP "|"; "]" ->
<:expr< $cparser_match loc e po pcl$ >>
| "match"; e = SELF; "with"; "parser"; po = OPT ipatt;
pc = parser_case ->
<:expr< $cparser_match loc e po [pc]$ >> ] ]
;
parser_case:
[ [ "[:"; sp = stream_patt; ":]"; po = OPT ipatt; "->"; e = expr ->
(sp, po, e) ] ]
;
stream_patt:
[ [ spc = stream_patt_comp -> [(spc, None)]
| spc = stream_patt_comp; ";";
sp = LIST1 stream_patt_comp_err SEP ";" ->
[(spc, None) :: sp]
| -> [] ] ]
;
stream_patt_comp_err:
[ [ spc = stream_patt_comp; eo = OPT [ "?"; e = expr -> e ] ->
(spc, eo) ] ]
;
stream_patt_comp:
[ [ "`"; p = patt; eo = OPT [ "when"; e = expr -> e ] -> SpTrm loc p eo
| p = patt; "="; e = expr -> SpNtr loc p e
| p = patt -> SpStr loc p ] ]
;
ipatt:
[ [ i = LIDENT -> <:patt< $lid:i$ >> ] ]
;
expr: LEVEL "simple"
[ [ "[:"; se = LIST0 stream_expr_comp SEP ";"; ":]" ->
<:expr< $cstream loc se$ >> ] ]
;
stream_expr_comp:
[ [ "`"; e = expr -> SeTrm loc e | e = expr -> SeNtr loc e ] ]
;
END;