NAME

bp - Bruce's Parsing Expression Grammar tool

SYNOPSIS

*options...*

pattern

\[\--

DESCRIPTION

bp is a tool that matches parsing expression grammars using a custom syntax.

OPTIONS

-v, --verbose: Print debugging information.
-e, --explain: Print a visual explanation of the matches.
-j, --json: Print a JSON list of the matches. (Pairs with --verbose for more detail)
-l, --list-files: Print only the names of files containing matches instead of the matches themselves.
-i, --ignore-case: Perform pattern matching case-insensitively.
-I, --inplace: Perform filtering or replacement in-place (i.e. overwrite files with new content).
-C, --confirm: During in-place modification of a file, confirm before each modification.
-r, --replace replacement: Replace all occurrences of the main pattern with the given string.
-s, --skip pattern: While looking for matches, skip over pattern occurrences. This can be useful for behavior like bp -s string (avoiding matches inside string literals).
-g, --grammar grammar-file: Load the grammar from the given file. See the GRAMMAR FILES section for more info.
-G, --git: Use git to get a list of files. Remaining file arguments (if any) are passed to git --ls-files instead of treated as literal files.
-c, --context N: The number of lines of context to print. If N is 0, print only the exact text of the matches. If N is "all", print the entire file. Otherwise, if N is a positive integer, print the whole line on which matches occur, as well as the N-1 lines before and after the match. The default value for this argument is 1 (print whole lines where matches occur).
-f, --format auto|fancy|plain: Set the output format. fancy includes colors and line numbers, plain includes neither, and auto (the default) uses fancy formatting only when the output is a TTY.
--help: Print the usage and exit.
pattern: The main pattern for bp to match. By default, this pattern is a string pattern (see the STRING PATTERNS section below).
files...: The input files to search. If no input files are provided and data was piped in, that data will be used instead. If neither are provided, bp will search through all files in the current directory and its subdirectories (recursively).

STRING PATTERNS

One of the most common use cases for pattern matching tools is matching plain, literal strings, or strings that are primarily plain strings, with one or two patterns. bp is designed around this fact. The default mode for bp patterns is "string pattern mode". In string pattern mode, all characters are interpreted literally except for the backslash (\), which may be followed by a bp pattern (see the PATTERNS section above). Optionally, the bp pattern may be terminated by a semicolon (;).

PATTERNS

bp patterns are based off of a combination of Parsing Expression Grammars and regular expression syntax. The syntax is designed to map closely to verbal descriptions of the patterns, and prefix operators are preferred over suffix operators (as is common in regex syntax).

Some patterns additionally have "multi-line" variants, which means that they include the newline character.

pat1 pat2: A sequence: pat1 followed by pat2
pat1 / pat2: A choice: pat1, or if it doesn't match, then pat2
.: Any character (excluding newline)
^: Start of a line
^^: Start of the text
$: End of a line (does not include newline character)
$$: End of the text
_: Zero or more whitespace characters, including spaces and tabs, but not newlines.
__: Zero or more whitespace characters, including spaces, tabs, newlines, and comments. Comments are undefined by default, but may be defined by a separate grammar file. See the GRAMMAR FILES section for more info.
"foo", 'foo': The literal string "foo". Single and double quotes are treated the same. Escape sequences are not allowed.
{foo}: The literal string "foo" with word boundaries on either end. Escape sequences are not allowed.
**`**c: The literal character c (e.g. `@ matches the "@" character)
**`c1,**c2: The literal character c1 or c2 (e.g. `a,e,i,o,u)
**`c1-**c2: The character range c1 to c2 (e.g. `a-z). Multiple ranges can be combined with a comma (e.g. `a-z,A-Z).
**\**esc: An escape sequence (e.g. \n, \x1F, \033, etc.)
**\esc1-**esc2: An escape sequence range from esc1 to esc2 (e.g. \x00-x1F)
\N: A special case escape that matches a "nodent": one or more newlines followed by the same indentation that occurs on the current line.
! pat: Not pat
[ pat ]: Maybe pat
N pat: Exactly N repetitions of pat (e.g. 5 `x matches "xxxxx")
N - M pat: Between N and M repetitions of pat (e.g. 2-3 `x matches "xx" or "xxx")
N**+** pat: At least N or more repetitions of pat (e.g. 2+ `x matches "xx", "xxx", "xxxx", etc.)
* pat: Some pats (zero or more, e.g. * `x matches "", "x", "xx", etc.)
+ pat: At least one pats (e.g. + `x matches "x", "xx", "xxx", etc.)
repeating-pat % sep: repeating-pat separated by sep (e.g. *word % `, matches zero or more comma-separated words)
.. pat: Any text (except newlines) up to and including pat
.. % skip pat: Any text (except newlines) up to and including pat, skipping over instances of skip (e.g. `"..`" % (`\.))
< pat: Just after pat (lookbehind)
> pat: Just before pat (lookahead)
@ pat: Capture pat
foo: The named pattern whose name is "foo". Pattern names come from definitions in grammar files or from named captures. Pattern names may contain dashes (-), but not underscores (_), since the underscore is used to match whitespace. See the GRAMMAR FILES section for more info.
@ name = pat: Let name equal pat (named capture). Named captures can be used as backreferences like so: @foo=word `( foo `) (matches "asdf(asdf)" or "baz(baz)", but not "foo(baz)")
pat => 'replacement': Replace pat with replacement. Note: replacement should be a string, and it may contain references to captured values: @0 (the whole of pat), @1 (the first capture in pat), **@**foo (the capture named foo in pat), etc. For example, @word _ @rest=(*word % _) => "@rest @1"
pat1 ~ pat2: Matches when pat1 matches and pat2 can be found within the text of that match. (e.g. comment ~ {TODO} matches comments that contain the word "TODO")
pat1 !~ pat2: Matches when pat1 matches, but pat2 can not be found within the text of that match. (e.g. comment ~ {IGNORE} matches only comments that do not contain the word "IGNORE")
name**:** pat: Define name to mean pat (pattern definition)
(!) error-pat: If error-pat matches, bp will not print any results in this file and instead print an error message to STDERR highlighting the matching position of error-pat in the file and printing the text of error-pat as an error message. Then, bp will exit with a failure status and not process any further files.
# comment: A line comment

GRAMMAR FILES

bp allows loading extra grammar files, which define patterns which may be used for matching. The builtins grammar file is loaded by default, and it defines a few useful general-purpose patterns. For example, it defines the parens rule, which matches pairs of matching parentheses, accounting for nested inner parentheses:

bp -p '"my_func" parens'

bp also comes with a few grammar files for common programming languages, which may be loaded on demand. These grammar files are not comprehensive syntax definitions, but only some common patterns. For example, the c++ grammar file contains definitions for //-style line comments as well as /*...*/-style block comments. Thus, you can find all comments with the word "TODO" with the following command:

bp -g c++ -p 'comment~{TODO}' *.cpp

EXAMPLES

ls | bp foo: Find files containing the string "foo" (a string pattern)
ls | bp '.c\$' -r '.h': Find files ending with ".c" and replace the extension with ".h"
bp -p '{foobar} parens' my_file.py: Find the word "foobar", followed by a pair of matching parentheses in the file my_file.py
bp -g html -p 'element ~ (^^"<a ")' foo.html: Using the html grammar, find all elements matching the tag a in the file foo.html
bp -g python -p 'comment~{TODO}' *.py: Find all comments with the word "TODO" in local python files.

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