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| -rw-r--r-- | build/camlp4-bootstrap-recipe.txt | 164 |
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diff --git a/build/camlp4-bootstrap-recipe.txt b/build/camlp4-bootstrap-recipe.txt new file mode 100644 index 0000000000..567e3affde --- /dev/null +++ b/build/camlp4-bootstrap-recipe.txt @@ -0,0 +1,164 @@ +=== Initial setup === + make clean + ./build/distclean.sh + ./configure -prefix `pwd`/_install + ./build/world.sh byte + # Go to "Bootstrap camlp4" + +=== Install the bootstrapping camlp4 processor === + ./build/install.sh + # Either extend your PATH with _install + export PATH=`pwd`/_install:$PATH + # Or copy just the needed files (for better understanding) + cp _build/camlp4/camlp4boot.byte <somewhereinPATH>/bin/camlp4boot + cp _build/camlp4/camlp4o.byte <somewhereinPATH>/bin/camlp4o + +=== Build camlp4 === + # This step is not needed right after a "./build/world.sh byte" + ./build/camlp4-byte-only.sh + +=== Bootstrap camlp4 === + # First "Build camlp4" + # Then "Install the bootstrapping camlp4 processor" + ./build/camlp4-bootstrap.sh + # If the fixpoint not is reached yet + # Go to "Bootstrap camlp4" + # Otherwise + # Have a look at the changes in + # camlp4/boot it may be a good idea to commit them + +=== Case study "let open M in e" === + + Open the revised parser + Camlp4Parsers/Camlp4OCamlRevisedParser.ml + + Look for similar constructs, indeed rules + that starts by the same prefix should in + the same entry. It is simpler to stick + them close to each other. + + [ "let"; r = opt_rec; ... + | "let"; "module"; m = a_UIDENT; ... + + So we naturally add something like + + | "let"; "open"; ... + + Then have a look to the "open" construct: + + | "open"; i = module_longident -> + + So we need a module_longident, it becomes: + + | "let"; "open"; i = module_longident; "in"; e = SELF -> + + Then we leave a dummy action but very close to what we want + in the end: + + | "let"; "open"; i = module_longident; "in"; e = SELF -> + <:expr< open_in $id:i$ $e$ >> + + Here it is just calling a (non-existing) function called open_in. + + Check that there is no other place where we have to duplicate this + rule (yuk!). In our case it is! The sequence entry have the "let" + rules again. + + Then go into Camlp4Parsers/Camlp4OCamlParser.ml and look for other + occurences. + + When copy/pasting the rule take care of SELF occurences, you may + have to replace it by expr and expr LEVEL ";" in our case. + + The return type of the production might be different from expr in + our case an action become <:str_item<...>> instead of <:expr<...> + + Watch the DELETE_RULE as well, in our case I'm searching for the + literal string "let" in the source: + + DELETE_RULE Gram expr: "let"; "open"; module_longident; "in"; SELF END; + + Then build and bootstrap. + + Then you can at last extend the AST, go in: + + Camlp4/Camlp4Ast.partial.ml + + And add the "open in" constructor (at the end). + + (* let open i in e *) + | ExOpI of loc and ident and expr + + Then build. Bootstrap once and build again. + + We get a single warning in Camlp4/Struct/Camlp4Ast2OCamlAst.ml but + don't fix it now. + + Then I hacked the camlp4/boot/camlp4boot.ml to generate: + Ast.ExOpI(_loc, i, e) + instead of + Ast.ExApp(_loc .... "open_in" ... i ... e ...) + + Build. Bootstrap once and build again. + + Then change the parsers again and replace the + open_in $id:i$ $e$ + by + let open $i$ in $e$ + + Then change the Parsetree generation in + Camlp4/Struct/Camlp4Ast2OCamlAst.ml + + | <:expr@loc< let open $i$ in $e$ >> -> + mkexp loc (Pexp_open (long_uident i) (expr e)) + + Change the pretty-printers as well (drawing inspiration in + "let module" in this case): + + In Camlp4/Printers/OCaml.ml: + | <:expr< let open $i$ in $e$ >> -> + pp f "@[<2>let open %a@]@ @[<2>in@ %a@]" + o#ident i o#reset_semi#expr e + And at the end of #simple_expr: + <:expr< let open $_$ in $_$ >> + + Have a look in Camlp4/Printers/OCamlr.ml as well. + +=== Second case study "with t := ..." === + +1/ Change the revised parser first. +Add new parsing rules for := but keep the old actions for now. + +2/ Change Camlp4Ast.partial.ml, add: + (* type t := t *) + | WcTyS of loc and ctyp and ctyp + (* module i := i *) + | WcMoS of loc and ident and ident + +3/ Build and bootstrap once. + +4/ Change the generated camlp4/boot/camlp4boot.ml: + Look for ":=" and change occurences of + WcMod by WcMoS and WcTyp by WcTyS + +5/ Build (DO NOT bootstrap) + "Install the bootstrapping camlp4 processor" + +6/ Change the required files: + Camlp4/Printers/OCaml.ml: + just copy/paste&adapt what is done for + "... with type t = u" and + "... with module M = N" + Camlp4/Struct/Camlp4Ast2OCamlAst.ml: + I've factored out a common part under + another function and then copy/pasted. + Camlp4Parsers/Camlp4OCamlRevisedParser.ml: + Change the <:with_constr< type $...$ = $...$ >> + we've introduced earlier by replacing the '=' + by ':='. + Camlp4Parsers/Camlp4OCamlParser.ml: + Copy paste what we have done in Camlp4OCamlRevisedParser + and but we need to call opt_private_ctyp instead of + ctyp (just like the "type =" construct). + +7/ Build & Bootstrap |