Lazy record fields by samoht · Pull Request #48 · ocaml/ocaml

samoht · 2014-04-29T22:41:09Z

Support for lazy record fields.

See http://www.lexifi.com/blog/ocaml-extensions-lexifi-semi-implicit-laziness

Inspired from http://www.lexifi.com/blog/ocaml-extensions-lexifi-semi-implicit-laziness Not yet checked if pattern-matching is broken or not.

ygrek · 2014-04-30T04:02:56Z

My two cents : the initialization of lazy record fields feels a bit too implicit. When glancing through the code it stands like an immediate evaluation.. Maybe add a bit more explicitness there?

type t = { x: int; lazy s: string; }
let make x = {x; lazy s = string_of_int x}

It even gains some symmetry to the lazy let feature (hope to see that one upstreamed too!).

gasche · 2014-04-30T04:56:33Z

A fairly problematic thing with this proposal (apparently not implemented in this early patch) is the lazy pattern syntax in record patterns: fun {x; lazy s} -> x,s keeps s thunked, while fun {x; s} -> x,s forces it... which is exactly the reverse of the semantics of lazy p (as forcing) in patterns.

alainfrisch · 2014-04-30T07:51:55Z

We now have some experience with this lazy-field feature at LexiFi, and honestly, I've a mixed feeling about it. While I stand behind the local "lazy let" / "lazy let rec", lazy fields have proven to make the code harder to maintain. It's too easy for a programmer to forget about the laziness and force the field without thinking about it (e.g. through a record pattern, while the continuation only needs the value of the field under some conditions). I'm actually considering removing the feature from our local version... "lazy let"s are much more local, and also much more useful (esp. for GUI programming).

xavierleroy · 2014-04-30T09:57:06Z

The old Caml V3.1 ("Caml Heavy") had a similar feature back in the late
1980's. When I designed Caml Light, I chose to abandon this feature,
because I felt that lazyness in a strict, imperative language like Caml
must be introduced and forced explicitly by the programmer; it is just too
confusing otherwise. 25 years later, I stand by this viewpoint. We now
have fairly lightweight syntax for suspending computations and for forcing
lazy values in patterns, so the syntactic overhead of being explicit is low.

samoht · 2014-05-01T10:06:56Z

Thanks for your comments, closing that PR then. It was still a good exercice for me anyway.

Rename 'delegate' to 'reperform' and 'DELEGATE' to 'REPERFORM'

don't take all the full pools in one go

173842c Merge flambda-backend changes ed7eba2 Remove leading space from LINE. (oxcaml/oxcaml#484) bd61170 Bump magic numbers (ocaml#5) c50c47d Add CI builds with local allocations enabled 1412792 Move local allocations support behind '-extension local' 6d8e42a Better tail call behaviour in caml_applyN c7dac3d Typemod: toplevel bindings escape even if no variables are bound 82d6c3e Several fixes for partial application and currying d05c70c Pprintast support for new local syntax e0e62fc Typecheck x |> f y as (f y x), not ((f y) x) d7e34ce Remove autogeneration of @ocaml.curry b9a0593 Port oxcaml/oxcaml#493 0a872d9 Code review fixes from oxcaml/oxcaml#491 6c168bb Remove local allocation counting 3c6e7f0 Code review fixes from oxcaml/oxcaml#478 bb97207 Rename Lambda.apply_position a7cb650 Quieten Makefile when runtime dep files are not present c656dc9 Merge flambda-backend changes 11b5424 Avoid printing double spaces in function argument lists 7751faa Restore locations to Typedtree.{pat,let}_bound_idents_full e450b6c add build_ocaml_compiler.sexp 0403bb3 Revert PR 9895 to continue installing VERSION b3447db Ensure new local attributes are namespaced properly 7f213fc Allow empty functions again 8f22ad8 Bugfix: ensure local domain state is initialised 80f54dd Bugfix for Selectgen with regions e8133a1 Fix external-external signature inclusion 9840051 Bootstrap d879f23 Merge remote-tracking branch 'jane/local-reviewed' into local-merge 94454f5 Use Local_store for the local allocations ref 54a164c Create fewer regions, according to typechecking (ocaml#59) 1c2479b Merge flambda-backend changes ce34678 Fix printing of modes in return types 91f2281 Hook mode variable solving into Btype.snapshot/backtrack 54e4b09 Move Alloc_mode and Value_mode to Btype ff4611e Merge flambda-backend changes ce62e45 Ensure allocations are initialised, even dead ones 6b6ec5a Fix the alloc.ml test on 32-bit builds 81e9879 Merge flambda-backend changes 40a7f89 Update repo URL for ocaml-jst, and rename script. 0454ee7 Add some new locally-allocating primitives (ocaml#57) 8acdda1 Reset the local stack pointer in exception handlers (ocaml#56) 8dafa98 Improve typing for (||) and (&&) (ocaml#55) 8c64754 Fix make_check_all_arches (ocaml#54) b50cd45 Allow arguments to primitives to be local even in tail position (ocaml#53) cad125d Fix modes from or-patterns (ocaml#50) 4efdb72 Fix tailcalls tests with inlining (ocaml#52) 4a795cb Flambda support (ocaml#49) 74722cb Add [@ocaml.principal] and [@ocaml.noprincipal] attributes, and use in oo.mli 6d7d3b8 Ensure that functions are evaluated after their arguments (flambda-backend ocaml#353) 89bda6b Keep Sys.opaque_identity in Cmm and Mach (port upstream PR 9412) a39126a Fix tailcalls within regions (ocaml#48) 4ac4cfd Fix stdlib manpages build 3a95f5e Merge flambda-backend changes efe80c9 Add jane/pull-flambda-patches script fca94c4 Register allocations for Omitted parameter closures (ocaml#47) 103b139 Remove various FIXMEs (ocaml#46) 62ba2c1 Bootstrap a0062ad Allow local allocations for various primitives (ocaml#43) 7a2165e Allow primitives to be poly-moded (ocaml#43) 2af3f55 Fix a flaky test by refactoring TypePairs (ocaml#10638) 58dd807 Bootstrap ee3be10 Fix modes in build_apply for partial applications fe73656 Tweak for evaluation order of labelled partial applications (ocaml#10653) 0527570 Fix caml_modify on local allocations (ocaml#40) e657e99 Relax modes for `as` patterns (ocaml#42) f815bf2 Add special mode handling for tuples in matches and let bindings (ocaml#38) 39f1211 Only take the upper bounds of modes associated with allocations (ocaml#37) aec6fde Interpret arrow types in "local positions" differently c4f3319 Bootstrap ff6fdad Add some missing regions 40d586d Bootstrap 66d8110 Switch to a system with 3 modes for values f2c5a85 Bugfix for Comballoc with local allocations. (ocaml#41) 83bcd09 Fix bug with root scanning during compaction (ocaml#39) 1b5ec83 Track modes in Lambda.lfunction and onwards (ocaml#33) f1e2e97 Port ocaml#10728 56703cd Port ocaml#10081 eb66785 Support local allocations in i386 and fix amd64 bug (ocaml#31) c936b19 Disallow local recursive non-functions (ocaml#30) c7a193a GC support for local allocations (ocaml#29) 8dd7270 Nonlocal fields (ocaml#28) e19a2f0 Bootstrap 694b9ac Add syntax to the parser for local allocations (ocaml#26) f183008 Lower initial stack size 918226f Allow local closure allocations (ocaml#27) 2552e7d Introduce mode variables (ocaml#25) bc41c99 Minor fixes for local allocations (ocaml#24) a2a4e60 Runtime and compiler support for more local allocations (ocaml#23) d030554 Typechecking for local allocations (ocaml#21) 9ee2332 Bugfix missing from ocaml#20 02c4cef Retain block-structured local regions until Mach. 86dbe1c amd64: Move stack realloc calls out-of-line 324d218 More typing modes and locking of environments a4080b8 Initial version of local allocation (unsafe) git-subtree-dir: ocaml git-subtree-split: 173842c

* initial import * use latest mdx and fix if_statement tutorial * add missing presentations and a few links

samoht added 3 commits April 29, 2014 23:38

Add some basic tests for lazy records

fcd3faa

Update .depend

1f4418e

samoht changed the title ~~Lazy field~~ Lazy record fields Apr 29, 2014

samoht closed this May 1, 2014

lpw25 pushed a commit to lpw25/ocaml that referenced this pull request Jun 12, 2016

Merge pull request ocaml#48 from clappski/refactor-delegate

31b4f3d

Rename 'delegate' to 'reperform' and 'DELEGATE' to 'REPERFORM'

vicuna mentioned this pull request Mar 14, 2019

OCaml SIGSEGV in invert_pointer_at() (OCaml Garbage Collector / Compaction) #7431

Closed

anmolsahoo25 pushed a commit to anmolsahoo25/ocaml that referenced this pull request Aug 25, 2020

Merge pull request ocaml#48 from sadiqj/stw_restrict_global_full_pools

c45905f

don't take all the full pools in one go

lpw25 added a commit to lpw25/ocaml that referenced this pull request Nov 21, 2021

Fix tailcalls within regions (ocaml#48)

a39126a

EmileTrotignon pushed a commit to EmileTrotignon/ocaml that referenced this pull request Jan 12, 2024

partial import of workshops (ocaml#48)

731e467

* initial import * use latest mdx and fix if_statement tutorial * add missing presentations and a few links

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Lazy record fields#48

Lazy record fields#48
samoht wants to merge 3 commits intoocaml:trunkfrom
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samoht commented Apr 29, 2014

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ygrek commented Apr 30, 2014

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gasche commented Apr 30, 2014

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alainfrisch commented Apr 30, 2014

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xavierleroy commented Apr 30, 2014

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samoht commented May 1, 2014

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samoht commented Apr 29, 2014

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ygrek commented Apr 30, 2014

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gasche commented Apr 30, 2014

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alainfrisch commented Apr 30, 2014

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xavierleroy commented Apr 30, 2014

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samoht commented May 1, 2014

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