This patch fixes a problem introduced last year when the GF shell was
refactored to allow more commands to be treated uniformly and be part
of pipes. The cc command was one of those commands, but unfortunately this
introduced a parsing problem, e.g.
> cc "last"
constant not found: last
> cc "last"++"year"
command not parsed: cc "last"++"year"
This happened because the generic command line parser in
GF.Command.{Abstract,Parse} assumes that all commands have an argument of
type PGF.Expr. Commands that expect other types of arguments have to
use PGF.showExpr combined with other conversion to the argument type they
expect. The cc command excpets a GF.Grammar.Term, and unfortunately not
all terms survice the roundtrip through PGF.Expr, in part because of
an additional hack to allow strings to be roundtripped through PGF.Expr
without adding superfluous double quotes.
To solve the problem, this patch
+ makes room for arguments of type Term in the Argument type in
GF.Command.Abstract.
+ makes a special case for the cc command in GF.Command.Parse, by
calling the partial parser 'runPartial pTerm' recently added in
GF.Grammar.Lexer and GF.Grammar.Parser. Care was taken so that
that "|" and ";" can be used both inside terms and as separators between
commands in the shell, e.g. things like the following now work:
> cc ("a"|"b") | ps -lexcode
variants { "a" ; "b" }
+ introduces a type CommandArgument that replaces [Expr] as the
type of values passed between commands in pipes. It has room for
values of type [Expr], [String] and Term, thus eliminating the need
to roundtrip through the Expr type all the time.
The hack to avoid adding superfluous quotes when strings are
roundtripped through Expr has been left in place for now,
but can probably be removed.
Lexer.x: Change the parser monad type P to allow the remaining input to
be returned after a partial parse. Add function
runPartial :: P t -> String -> Either (Posn, String) (String, t)
Parser.y: Add a partial parser pTerm for nonterminal Exp1.
Re-export runPartial.
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.
The matchPrefix function is used in str2strings and the partial evaluator to
compute pre{...} tokens. But unlike the description in the GF book and
the implementation in the run-time system, matchPrefix looked at
the concatenation(!) of all following tokens and not just the next token
when deciding how to compute a pre{...} token.
This is a backwards incompatible change, but it is subtle and probably won't
cause any problems. In particular, the example grammars are unaffected.
This makes the output from PGF.showExpr (and other Haskell code that uses
the Prelude.show function to show strings) parsable as GF source code in
more cases.
This is a workaround for the problem that GHC's implementation of the show
function uses numeric escapes for printable non-ASCII characters, e.g.
show "dålig" = "d\229lig"...
* "gf -make -j=n" uses n parallel threads.
* "gf -make -j" adapts to the number of processors in the system.
This mimics how "cabal build -j" and "ghc --make -j" works.
Support for this is implemented in the new module GF.System.Concurrency and
it depends on the function Control.Concurrent.setNumCapabilities, which is
only available in GHC>=7.6 (base>=4.6). GF can still be compiled with
GHC<7.6, but then you have to use +RTS -N -RTS to take advantage of
multicore processors.
To detect the number of processors in the system, the code depends on a
foreign import of a C function in the GHC run-time system.
These changes are inspired by the gf -cshell implementation of these commands.
The output of the linearize command has been changed to remove superfluous
blank lines and commas, and deliver the result as a list of strings instead of
a single multi-line string. This makes it possible to use -all and pipe the
results to the parse command. This also means that with -treebank -all,
the language tag will be repeated for each result from the same language.
The parse command, when trying to parse with more than one language, would
"forget" other results after a failed parse, and thus not send all
successful parses through the pipe. For example, if English is not the first
language in the grammar,
p "hello" | l
would output nothing, instead of translations of "hello" to all languages,
forcing the user to write
p -lang=Eng "hello" | l
instead, to get the expected result. The cause of this behaviour was in the
function fromParse, which was rather messy, so I assume it is not intentional,
but the result of a programming mistake at some point.
The fromParse function has now been refactored from a big recursive function
into
fromParse opts = foldr (joinPiped . fromParse1 opts) void
where the helper functions fromParse1 deals with a single parse result and
joinPiped combines multiple parse results.
Even though the -lang flag was handled in the implementation, it was not
documented, and GF.Command.Interpreter rejects undocumented flags:
option not interpreted: lang
This must be a fairly old bug, so it suggests that the vp command isn't used
much...
pg supports only the -funs, -cats and -langs output modes.
ai IDENTIFIER shows info about a category or a function. ai can not type check
and refine metavariables in expressions.
Options -all and -list use PGF2.linearizeAll, which lists all variants, but
not all forms...
Also, there is no attempt to be compatible with the output from the Haskell
run-rime shell, which produces superfluous blank lines (-all) or
commas (-list), and mixes tagged and untagged lines (-treebank -all).
The print_history command was among the commands implemented in an ad-hoc
way instead of being handled by the command line interpreter, which means
it could not be used in a pipe, as in the example in the help info.
The refactoring in the previous patch made this old bug easy to fix.
Also fixed a bug in the "empty" command, introduced when moving the PGF from
CommandEnv to GFEnv.
TODO: fix the undocumented eh command. A comment in the help info for
print_history, and some commented out old code, suggest that eh means
"execute_history", but at present it does nothing...
+ Generalize the CommandInfo type by parameterizing it on the monad
instead of just the environment.
+ Generalize the commands defined in
GF.Command.{Commands,Commands2,CommonCommands,SourceCommands,HelpCommand}
to work in any monad that supports the needed operations.
+ Liberate GF.Command.Interpreter from the IO monad.
Also, move the current PGF from CommandEnv to GFEnv in
GF.Interactive, making the command interpreter even more generic.
+ Use a state monad to maintain the state of the interpreter in
GF.{Interactive,Interactive2}.
These commands are now implemented as regular commands (i.e. using the
CommandInfo data type) in the new module GF.Command.SourceCommands.
The list of commands exported from GF.Command.Commmands now called pgfCommands
instead of allCommands.
The list allCommands of all commands is now assembled
from sourceCommands, pgfCommands, commonCommands and helpCommand in
GF.Interactive.
