Instead of passing around references to the environment, just treat it
as a global. The old way was just the remains of an idea to make the
environment immutable and keep the interpreter from manipulating any
global state. By making everything global and mutable, we will have
less impedance mismatch with POSIX going forward.
The following changelog is only a sketch, since nearly every function
has changed.
* geesh/environment.scm: Replace this module with one that treats the
environment as a global resource.
* tests/environment.scm: Delete file.
* Makefile.am: Remove it from the list of tests.
* geesh/shell.scm, geesh/eval.scm, geesh/repl.scm, geesh/word.scm,
geesh/built-ins/break.scm, geesh/built-ins/continue.scm,
geesh/built-ins/echo.scm, geesh/built-ins/export.scm,
geesh/built-ins/false.scm, geesh/built-ins/read.scm,
geesh/built-ins/readonly.scm, geesh/built-ins/set.scm,
geesh/built-ins/true.scm, geesh/built-ins/unset.scm: Remove 'env'
parameters and use the new environment module.
* .dir-locals.el: Update indentation of functions that no longer take
an 'env' parameter and add with-arguments, with-environ, and
with-variables from the new environment module.
* tests/shell.scm, tests/word.scm: Update environment creation and
manipulation in tests.
* geesh/word.scm (expand-word): Change the 'split?' keyword argument
to 'output', accepting one of 'fields', 'string', or 'pattern'.
(word->qword): Update calls.
* geesh/eval.scm (eval-word): Same as 'expand-word' above.
(eval-redir): Update call.
(eval-sh): Update calls.
* geesh/word.scm (split-fields): Move handling of list words into
'wedge-apart' so that they get handled in recursive calls.
* tests/word.scm: Add a test for this.
* geesh/word.scm (split-fields): Make an empty string yield zero
fields (an empty list).
* tests/word.scm: Update tests and add tests to make sure that quoted
empty strings are preserved.
* geesh/word.scm (split-fields): Handle a special '<sh-at>' qword
form, so that a quoted '$@' reference can still be split.
(argument-separator): New function.
(remove-quotes): Handle the '<sh-at>' form when it should not be
split. This requires knowing how to concatenate arguments, so add an
'ifs' parameter.
(expand-word): Pass 'ifs' to 'remove-quotes'.
We used to model 'IFS' as a character set, but when handling special
parameters, the order of the characters matters. Since it is also an
environment variable, it makes sense to treat as a string (rather than
a list).
* geesh/word.scm (split-fields): Treat 'ifs' as a string instead of a
character set.
(expand-word): Get 'ifs' from the environment if available or use a
default string otherwise.
Instead of using an environment variable named '?', we will use a
special environment field called 'status'. This lets us get rid of a
lot of number-string conversions (since an environment variable has to
have a string value).
* geesh/environment.scm (<environment>): Add a 'status' field.
(make-environment): Set it to 0 by default.
* geesh/repl.scm (run-repl): Use new field in place of '?' variable.
* geesh/shell.scm (exec-utility, sh:and, sh:exec-let, sh:for, sh:not,
sh:or, sh:pipeline, sh:subshell, sh:substitute-command): Ditto.
* geesh/word.scm (parameter-ref): New function that handles both
special parameters (e.g., '?') and variables.
(parameter-ref*): Like 'var-ref*', but for 'parameter-ref'.
(word->qword): Replace 'var-ref' and 'var-ref*' with 'parameter-ref'
and 'parameter-ref*' respectively.
Timothy Sample