+ Abstract syntax now is converted directly from the Grammar and not via PGF,
so you can use `gf -batch -no-pmcfg -f canonical_gf ...`, to export to
canonical_gf while skipping PMCFG and PGF file generation completely.
+ Flags that are normally copied to PGF files are now included in the
caninical_gf output as well (in particular the startcat flag).
This output format converts a GF grammar to a "canonical" GF grammar. A
canonical GF grammar consists of
- one self-contained module for the abstract syntax
- one self-contained module per concrete syntax
The concrete syntax modules contain param, lincat and lin definitions,
everything else has been eliminated by the partial evaluator, including
references to resource library modules and functors. Record types
and tables are retained.
The -output-format canonical_gf option writes canonical GF grammars to a
subdirectory "canonical/". The canonical GF grammars are written as
normal GF ".gf" source files, which can be compiled with GF in the normal way.
The translation to canonical form goes via an AST for canonical GF grammars,
defined in GF.Grammar.Canonical. This is a simple, self-contained format that
doesn't cover everyting in GF (e.g. omitting dependent types and HOAS), but it
is complete enough to translate the Foods and Phrasebook grammars found in
gf-contrib. The AST is based on the GF grammar "GFCanonical" presented here:
https://github.com/GrammaticalFramework/gf-core/issues/30#issuecomment-453556553
The translation of concrete syntax to canonical form is based on the
previously existing translation of concrete syntax to Haskell, implemented
in module GF.Compile.ConcreteToHaskell. This module could now be reimplemented
and simplified significantly by going via the canonical format. Perhaps exports
to other output formats could benefit by going via the canonical format too.
There is also the possibility of completing the GFCanonical grammar
mentioned above and using GF itself to convert canonical GF grammars to
other formats...
* In GHC 8.4.1, the operator <> has become a method of the Semigroup class
and is exported from the Prelude. This is unfortunate, since <> is also
exported from the standard library module Text.PrettyPrint, so in any
module that defines a pretty printer, there is likely to be an ambiguity.
This affects ~18 modules in GF. Solution:
import Prelude hiding (<>)
This works also in older versions of GHC, since GHC does't complain if
you hide something that doesn't exists.
* In GHC 8.4.1, Semigroup has become a superclass of Monoid. This means
that anywhere you define an instance of the Monoid class you also have to
define an instance in the Semigroup class.
This affects Data.Binary.Builder in GF. Solution: conditionally define
a Semigroup instance if compiling with base>=4.11 (ghc>=8.4.1)
This is implemented as a simple post-processing step after partial evaluation
to try compute pre{...} tokens in token sequences. Nothing is done to deal
with intervening free variants.
This was done in response to a query from René T on the gf-dev mailing list.
Becacuse of the new special tokens added to the Symbol type, .gfo and .pgf
files produced with the current version of GF can not always be used with
older versions of GF and the PGF run-time system.
The PGF version number was increased from (2,0) to (2,1). GF can still
read version (2,0) and (1,0), so old PGF files continue to work.
The GFO version was increased from "GF03" to "GF04".
For further separation of pretty printing concerns from conversion concerns,
the Haskell AST and pretty printer has been moved to its own module,
GF.Haskell, also allowing it to be reused in other places where Haskell
code is generated.
If the enumaration of table parameter values fails during the static
traversal phase, try again in the dynamic computation phase, when the values
of bound variables are known.
This is necessary to properly deal with generic table construction in opers,
like the ones found in prelude/Coordination.gf, e.g.
consTable : (P : PType) -> ... = \P ... -> {s1 = table P {...} ; ... }
GF.Compile.Optimize.mkLinReference can fail and cause this error because
the helper function inside it applies msum to a list that might be empty
(if there is a record type that does not contain a field of type Str).
This means that it can return mzero::Err, i.e.
Bad "error (no reason given)"
which can slip through the top level test that only catches Bad "no string".
2 modules: Name clashes caused by Applicative-Monad change in Prelude
2 modules: Ambiguities caused by Foldable/Traversable in Prelude
2 modules: Backwards incompatible changes in time-1.5 for defaultTimeLocale
9 modules: {-# LANGUAGE FlexibleContexts #-} (because GHC checks inferred types
now, in addition to explicitly given type signatures)
Also silenced warnings about tab characters in source files.
