Release dwgrep 0.4 · pmachata/dwgrep

Fix file name shown when -H is passed and no files are given on the command
line. Before, it was <no-file> somewhere and empty string elsewhere. Now it's
<no-file> everywhere.
Support passing arguments to scripts from the command line. Two new command
line flags are available: -a for passing in simple strings, and --a, whose
argument is parsed as Zwerg expression, and TOS of the yielded stack is passed
to the script. The arguments are pushed to input stack of the query
expression, which can bind them using lexical scope, or use arbitrarily.
- Fixes #13: Support passing arguments to scripts from command line
For example:
```
$ ./dwgrep/dwgrep foo --a DW_AT_language -e '(|At| entry attribute (label == At))'
language	C99
```
Position reported at Dwarf values passed in from command line used to be
always 0. Now it's the file's position on command line:
```
$ dwgrep /bin/true /bin/false -he '[|Dw| Dw name, Dw pos]'
["/bin/true", 0]
["/bin/false", 1]
```

Fix a bug introduced in 0.3 where a captured expression wasn't reset properly,
due to which after the first list was produced, the following lists were all
empty.

Support DW_DEFAULTED_* suite of constants. Use them to decode DW_AT_defaulted.
Support decoding of DWARF 5 attributes DW_AT_string_length_bit_size,
DW_AT_string_length_byte_size, DW_AT_rank, DW_AT_alignment,
DW_AT_str_offsets_base, DW_AT_addr_base, DW_AT_rnglists_base, and
DW_AT_loclists_base.
Unhandled attributes in the DW_AT_lo_user .. DW_AT_hi_user area are now
decoded implicitly as unsigned.
Integral attributes with encoding DW_ATE_boolean are now decoded as booleans,
not as plain unsigned numbers.
Attributes with block forms whose length is 1, 2, 4 or 8 bytes, are decoded as
if they were integrals. Encoding of the attribute determines how exactly will
the integral be decoded.

Allow bindings named the same way as a built-in word. This is important for
forward-compatibility: adding built-in words doesn't break existing queries
that use that name for a binding.
- Fixes #29: Allow naming variables like builtins

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