class Asciidoctor::Reader
Public: Methods for retrieving lines from AsciiDoc source files
Attributes
Public: Get the 1-based offset of the current line.
Public: Control whether lines are processed using Reader#process_line
on first visit (default: true)
Public Class Methods
Public: Initialize the Reader
object
# File lib/asciidoctor/reader.rb, line 39 def initialize data = nil, cursor = nil, opts = {} if !cursor @file = @dir = nil @path = '<stdin>' @lineno = 1 # IMPORTANT lineno assignment must proceed prepare_lines call! elsif ::String === cursor @file = cursor @dir, @path = ::File.split @file @lineno = 1 # IMPORTANT lineno assignment must proceed prepare_lines call! else @file = cursor.file @dir = cursor.dir @path = cursor.path || '<stdin>' if @file unless @dir # REVIEW might to look at this assignment closer @dir = ::File.dirname @file @dir = nil if @dir == '.' # right? end unless cursor.path @path = ::File.basename @file end end @lineno = cursor.lineno || 1 # IMPORTANT lineno assignment must proceed prepare_lines call! end @lines = data ? (prepare_lines data, opts) : [] @source_lines = @lines.dup @look_ahead = 0 @process_lines = true @unescape_next_line = false end
Public Instance Methods
Public: Advance to the next line by discarding the line at the front of the stack
Returns a Boolean indicating whether there was a line to discard.
# File lib/asciidoctor/reader.rb, line 257 def advance shift ? true : false end
# File lib/asciidoctor/reader.rb, line 518 def cursor Cursor.new @file, @dir, @path, @lineno end
Public: Check whether this reader is empty (contains no lines)
Returns true if there are no more lines to peek, otherwise false.
# File lib/asciidoctor/reader.rb, line 134 def empty? if @lines.empty? @look_ahead = 0 true else false end end
Public: Check whether there are any lines left to read.
If a previous call to this method resulted in a value of false, immediately returned the cached value. Otherwise, delegate to peek_line
to determine if there is a next line available.
Returns True if there are more lines, False if there are not.
# File lib/asciidoctor/reader.rb, line 122 def has_more_lines? if @lines.empty? @look_ahead = 0 false else true end end
Public: Get information about the last line read, including file name and line number.
Returns A String
summary of the last line read
# File lib/asciidoctor/reader.rb, line 525 def line_info %(#{@path}: line #{@lineno}) end
Public: Peek at the next line and check if it's empty (i.e., whitespace only)
This method Does not consume the line from the stack.
Returns True if the there are no more lines or if the next line is empty
# File lib/asciidoctor/reader.rb, line 149 def next_line_empty? peek_line.nil_or_empty? end
Public: Peek at the next line of source data. Processes the line if not already marked as processed, but does not consume it.
This method will probe the reader for more lines. If there is a next line that has not previously been visited, the line is passed to the Reader#process_line
method to be initialized. This call gives sub-classes the opportunity to do preprocessing. If the return value of the Reader#process_line
is nil, the data is assumed to be changed and Reader#peek_line
is invoked again to perform further processing.
If has_more_lines? is called immediately before peek_line
, the direct flag is implicitly true (since the line is flagged as visited).
direct - A Boolean flag to bypasses the check for more lines and immediately
returns the first element of the internal @lines Array. (default: false)
Returns the next line of the source data as a String
if there are lines remaining. Returns nothing if there is no more data.
# File lib/asciidoctor/reader.rb, line 171 def peek_line direct = false if direct || @look_ahead > 0 @unescape_next_line ? @lines[0][1..-1] : @lines[0] elsif @lines.empty? @look_ahead = 0 nil else # FIXME the problem with this approach is that we aren't # retaining the modified line (hence the @unescape_next_line tweak) # perhaps we need a stack of proxied lines (line = process_line @lines[0]) ? line : peek_line end end
Public: Peek at the next multiple lines of source data. Processes the lines if not already marked as processed, but does not consume them.
This method delegates to Reader#read_line
to process and collect the line, then restores the lines to the stack before returning them. This allows the lines to be processed and marked as such so that subsequent reads will not need to process the lines again.
num - The positive Integer number of lines to peek (must be greater than 0). direct - A Boolean indicating whether processing should be disabled when reading lines
Returns A String
Array
of the next multiple lines of source data, or an empty Array
if there are no more lines in this Reader
.
# File lib/asciidoctor/reader.rb, line 198 def peek_lines num, direct = false old_look_ahead = @look_ahead result = [] num.times do if (line = direct ? shift : read_line) result << line else @lineno -= 1 if direct break end end unless result.empty? unshift_all result @look_ahead = old_look_ahead if direct end result end
Internal: Prepare the lines from the provided data
This method strips whitespace from the end of every line of the source data and appends a LF (i.e., Unix endline). This whitespace substitution is very important to how Asciidoctor
works.
Any leading or trailing blank lines are also removed.
data - A String
Array
of input data to be normalized opts - A Hash
of options to control what cleansing is done
Returns The String
lines extracted from the data
# File lib/asciidoctor/reader.rb, line 85 def prepare_lines data, opts = {} if ::String === data if opts[:normalize] Helpers.normalize_lines_from_string data else data.split LF, -1 end else if opts[:normalize] Helpers.normalize_lines_array data else data.dup end end end
# File lib/asciidoctor/reader.rb, line 530 def prev_line_info %(#{@path}: line #{@lineno - 1}) end
Internal: Processes a previously unvisited line
By default, this method marks the line as processed by incrementing the look_ahead counter and returns the line unmodified.
Returns The String
line the Reader
should make available to the next invocation of Reader#read_line
or nil if the Reader
should drop the line, advance to the next line and process it.
# File lib/asciidoctor/reader.rb, line 110 def process_line line @look_ahead += 1 if @process_lines line end
Public: Get the remaining lines of source data joined as a String
.
Delegates to Reader#read_lines
, then joins the result.
Returns the lines read joined as a String
# File lib/asciidoctor/reader.rb, line 250 def read read_lines * LF end
Public: Get the next line of source data. Consumes the line returned.
Returns the String
of the next line of the source data if data is present. Returns nothing if there is no more data.
# File lib/asciidoctor/reader.rb, line 222 def read_line # has_more_lines? triggers preprocessor shift if @look_ahead > 0 || has_more_lines? end
Public: Get the remaining lines of source data.
This method calls Reader#read_line
repeatedly until all lines are consumed and returns the lines as a String
Array
. This method differs from Reader#lines
in that it processes each line in turn, hence triggering any preprocessors implemented in sub-classes.
Returns the lines read as a String
Array
# File lib/asciidoctor/reader.rb, line 235 def read_lines lines = [] # has_more_lines? triggers preprocessor while has_more_lines? lines << shift end lines end
Public: Return all the lines from `@lines` until we (1) run out them,
(2) find a blank line with :break_on_blank_lines => true, or (3) find a line for which the given block evals to true.
options - an optional Hash
of processing options:
* :break_on_blank_lines may be used to specify to break on blank lines * :skip_first_line may be used to tell the reader to advance beyond the first line before beginning the scan * :preserve_last_line may be used to specify that the String causing the method to stop processing lines should be pushed back onto the `lines` Array. * :read_last_line may be used to specify that the String causing the method to stop processing lines should be included in the lines being returned
Returns the Array
of lines forming the next segment.
Examples
data = [ "First line\n", "Second line\n", "\n", "Third line\n", ] reader = Reader.new data, nil, :normalize => true reader.read_lines_until => ["First line", "Second line"]
# File lib/asciidoctor/reader.rb, line 432 def read_lines_until options = {} result = [] shift if options[:skip_first_line] if @process_lines && options[:skip_processing] @process_lines = false restore_process_lines = true else restore_process_lines = false end if (terminator = options[:terminator]) break_on_blank_lines = false break_on_list_continuation = false else break_on_blank_lines = options[:break_on_blank_lines] break_on_list_continuation = options[:break_on_list_continuation] end skip_comments = options[:skip_line_comments] line_read = false line_restored = false complete = false while !complete && (line = read_line) complete = while true break true if terminator && line == terminator # QUESTION: can we get away with line.empty? here? break true if break_on_blank_lines && line.empty? if break_on_list_continuation && line_read && line == LIST_CONTINUATION options[:preserve_last_line] = true break true end break true if block_given? && (yield line) break false end if complete if options[:read_last_line] result << line line_read = true end if options[:preserve_last_line] unshift line line_restored = true end else unless skip_comments && (line.start_with? '//') && !(line.start_with? '///') result << line line_read = true end end end if restore_process_lines @process_lines = true @look_ahead -= 1 if line_restored && !terminator end result end
Public: Replace the next line with the specified line.
Calls Reader#advance
to consume the current line, then calls Reader#unshift
to push the replacement onto the top of the line stack.
replacement - The String
line to put in place of the next line (i.e., the line at the cursor).
Returns nothing.
# File lib/asciidoctor/reader.rb, line 300 def replace_next_line replacement shift unshift replacement nil end
Internal: Shift the line off the stack and increment the lineno
This method can be used directly when you've already called peek_line
and determined that you do, in fact, want to pluck that line off the stack. Use read_line
if the line hasn't (or many not have been) visited yet.
Returns The String
line at the top of the stack
# File lib/asciidoctor/reader.rb, line 498 def shift @lineno += 1 @look_ahead -= 1 unless @look_ahead == 0 @lines.shift end
Public: Skip blank lines at the cursor.
Examples
reader.lines => ["", "", "Foo", "Bar", ""] reader.skip_blank_lines => 2 reader.lines => ["Foo", "Bar", ""]
Returns the [Integer] number of lines skipped or nothing if all lines have been consumed (even if lines were skipped by this method).
# File lib/asciidoctor/reader.rb, line 321 def skip_blank_lines return if empty? num_skipped = 0 # optimized code for shortest execution path while (next_line = peek_line) if next_line.empty? shift num_skipped += 1 else return num_skipped end end end
Public: Skip consecutive lines containing line comments and return them.
Examples
@lines => ["// foo", "bar"] comment_lines = skip_comment_lines => ["// foo"] @lines => ["bar"]
Returns the Array
of lines that were skipped
# File lib/asciidoctor/reader.rb, line 349 def skip_comment_lines return [] if empty? comment_lines = [] while (next_line = peek_line) && !next_line.empty? if next_line.start_with? '//' if next_line.start_with? '///' if (ll = next_line.length) > 3 && next_line == '/' * ll comment_lines << shift comment_lines.push(*(read_lines_until(:terminator => next_line, :read_last_line => true, :skip_processing => true))) else break end else comment_lines << shift end else break end end comment_lines end
Public: Skip consecutive lines that are line comments and return them.
This method assumes the reader only contains simple lines (no blocks).
# File lib/asciidoctor/reader.rb, line 376 def skip_line_comments return [] if empty? comment_lines = [] # optimized code for shortest execution path while (next_line = peek_line) && !next_line.empty? if (next_line.start_with? '//') comment_lines << shift else break end end comment_lines end
Public: Advance to the end of the reader, consuming all remaining lines
Returns nothing.
# File lib/asciidoctor/reader.rb, line 395 def terminate @lineno += @lines.size @lines.clear @look_ahead = 0 nil end
Public: Get a summary of this Reader
.
Returns A string summary of this reader, which contains the path and line information
# File lib/asciidoctor/reader.rb, line 555 def to_s line_info end
Internal: Restore the line to the stack and decrement the lineno
# File lib/asciidoctor/reader.rb, line 505 def unshift line @lineno -= 1 @look_ahead += 1 @lines.unshift line end
Internal: Restore the lines to the stack and decrement the lineno
# File lib/asciidoctor/reader.rb, line 512 def unshift_all lines @lineno -= lines.size @look_ahead += lines.size @lines.unshift(*lines) end
Public: Push the String
line onto the beginning of the Array
of source data.
A line pushed on the reader using this method is not processed again. The method assumes the line was previously retrieved from the reader or does not otherwise contain preprocessor directives. Therefore, it is marked as processed immediately.
line_to_restore - the line to restore onto the stack
Returns nothing.
# File lib/asciidoctor/reader.rb, line 271 def unshift_line line_to_restore unshift line_to_restore nil end
Public: Push an Array
of lines onto the front of the Array
of source data.
Lines pushed on the reader using this method are not processed again. The method assumes the lines were previously retrieved from the reader or do not otherwise contain preprocessor directives. Therefore, they are marked as processed immediately.
Returns nothing.
# File lib/asciidoctor/reader.rb, line 285 def unshift_lines lines_to_restore unshift_all lines_to_restore nil end