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.
+ 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}.
+ Move type CommandInfo from GF.Command.Commands to a new module
GF.Commands.CommandInfo and make it independent of the PGF type.
+ Make the module GF.Command.Interpreter independent of the PGF type and
eliminate the import of GF.Command.Commands.
+ Move the implementation of the "help" command to its own module
GF.Command.Help
PGF exports the public, stable API.
PGF.Internal exports additional things needed in the GF compiler & shell,
including the nonstardard version of Data.Binary.
+ References to modules under src/compiler have been eliminated from the PGF
library (under src/runtime/haskell). Only two functions had to be moved (from
GF.Data.Utilities to PGF.Utilities) to make this possible, other apparent
dependencies turned out to be vacuous.
+ In gf.cabal, the GF executable no longer directly depends on the PGF library
source directory, but only on the exposed library modules. This means that
there is less duplication in gf.cabal and that the 30 modules in the
PGF library will no longer be compiled twice while building GF.
To make this possible, additional PGF library modules have been exposed, even
though they should probably be considered for internal use only. They could
be collected in a PGF.Internal module, or marked as "unstable", to make
this explicit.
+ Also, by using the -fwarn-unused-imports flag, ~220 redundant imports were
found and removed, reducing the total number of imports by ~15%.
The output from commands is represented as ([Expr],String), where the [Expr] is
used when data is piped between commands and the String is used for the final
output. The String can represent the same list of trees as the [Expr] and/or
contain diagnostic information.
Sometimes the data that is piped between commands is not a list of trees, but
e.g. a string or a list of strings. In those cases, functions like fromStrings
and toStrings are used to encode the data as a [Expr].
This patch introduces a newtype for CommandOutput and collects the functions
dealing with command output in one place to make it clearer what is going on.
It also makes it easier to change to a more direct representation of piped
data, and make pipes more "type safe", if desired.
+ The restrictions on arbitrary IO when GF is running in restricted mode is now
enforced in the types.
+ This hopefully also solves an intermittent problem when accessing the GF
shell through the web API provided by gf -server. This was visible in the
Simple Translation Tool and probably caused by some low-level bug in the
GHC IO libraries.
The dependency on PGFEnv has been moved from the list to the exec function of
the commands in the list. This means that the help command no longer needs
to generate a new list of commands and that the state of the shell
(type GF.Command.Interpreter.CommandEnv) no longer needs to contain the list
of commands.
