+'''
+This modules offer several free functions to help parse lines.
+More documentaton is below, but here is a quick guide to what
+they do. Optional arguments are marked by brackets.
+
+find_token(lines, token, start[, end[, ignorews]]):
+ Returns the first line i, start <= i < end, on which
+ token is found at the beginning. Returns -1 if not
+ found.
+ If ignorews is (given and) True, then differences
+ in whitespace do not count, except that there must be no
+ extra whitespace following token itself.
+
+find_token_exact(lines, token, start[, end]):
+ As find_token, but with ignorews True.
+
+find_tokens(lines, tokens, start[, end[, ignorews]]):
+ Returns the first line i, start <= i < end, on which
+ oen of the tokens in tokens is found at the beginning.
+ Returns -1 if not found.
+ If ignorews is (given and) True, then differences
+ in whitespace do not count, except that there must be no
+ extra whitespace following token itself.
+
+find_tokens_exact(lines, token, start[, end]):
+ As find_tokens, but with ignorews True.
+
+find_token_backwards(lines, token, start):
+find_tokens_backwards(lines, tokens, start):
+ As before, but look backwards.
+
+find_re(lines, rexp, start[, end]):
+ As find_token, but rexp is a regular expression object,
+ so it has to be passed as e.g.: re.compile(r'...').
+
+get_value(lines, token, start[, end[, default]):
+ Similar to find_token, but it returns what follows the
+ token on the found line. Example:
+ get_value(document.header, "\use_xetex", 0)
+ will find a line like:
+ \use_xetex true
+ and, in that case, return "true". (Note that whitespace
+ is stripped.) The final argument, default, defaults to "",
+ and is what is returned if we do not find anything. So you
+ can use that to set a default.
+
+get_quoted_value(lines, token, start[, end[, default]):
+ Similar to get_value, but it will strip quotes off the
+ value, if they are present. So use this one for cases
+ where the value is normally quoted.
+
+get_option_value(line, option):
+ This assumes we have a line with something like:
+ option="value"
+ and returns value. Returns "" if not found.
+
+del_token(lines, token, start[, end]):
+ Like find_token, but deletes the line if it finds one.
+ Returns True if a line got deleted, otherwise False.
+
+find_beginning_of(lines, i, start_token, end_token):
+ Here, start_token and end_token are meant to be a matching
+ pair, like "\begin_layout" and "\end_layout". We look for
+ the start_token that pairs with the end_token that occurs
+ on or after line i. Returns -1 if not found.
+ So, in the layout case, this would find the \begin_layout
+ for the layout line i is in.
+ Example:
+ ec = find_token(document.body, "</cell", i)
+ bc = find_beginning_of(document.body, ec, \
+ "<cell", "</cell")
+ Now, assuming no -1s, bc-ec wraps the cell for line i.
+
+find_end_of(lines, i, start_token, end_token):
+ Like find_beginning_of, but looking for the matching
+ end_token. This might look like:
+ bc = find_token_(document.body, "<cell", i)
+ ec = find_end_of(document.body, bc, "<cell", "</cell")
+ Now, assuming no -1s, bc-ec wrap the next cell.
+
+find_end_of_inset(lines, i):
+ Specialization of find_end_of for insets.
+
+find_end_of_layout(lines, i):
+ Specialization of find_end_of for layouts.
+
+is_in_inset(lines, i, inset):
+ Checks if line i is in an inset of the given type.
+ If so, returns starting and ending lines. Otherwise,
+ returns False.
+ Example:
+ is_in_inset(document.body, i, "\\begin_inset Tabular")
+ returns False unless i is within a table. If it is, then
+ it returns the line on which the table begins and the one
+ on which it ends. Note that this pair will evaulate to
+ boolean True, so
+ if is_in_inset(...):
+ will do what you expect.
+
+get_containing_inset(lines, i):
+ Finds out what kind of inset line i is within. Returns a
+ list containing what follows \begin_inset on the the line
+ on which the inset begins, plus the starting and ending line.
+ Returns False on any kind of error or if it isn't in an inset.
+ So get_containing_inset(document.body, i) might return:
+ ("CommandInset ref", 300, 306)
+ if i is within an InsetRef beginning on line 300 and ending
+ on line 306.
+
+get_containing_layout(lines, i):
+ As get_containing_inset, but for layout.
+
+
+find_nonempty_line(lines, start[, end):
+ Finds the next non-empty line.
+
+check_token(line, token):
+ Does line begin with token?
+
+is_nonempty_line(line):
+ Does line contain something besides whitespace?
+
+'''
+
+import re
+
+# Utilities for one line