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Class: SyntaxSuggest::BlockExpand

Relationships & Source Files
Inherits: Object
Defined in: lib/syntax_suggest/block_expand.rb

Overview

This class is responsible for taking a code block that exists at a far indentaion and then iteratively increasing the block so that it captures everything within the same indentation block.

def dog
  puts "bow"
  puts "wow"
end

block = .new(code_lines: code_lines)

.call(CodeBlock.new(lines: code_lines[1]))

puts block.to_s

=> puts “bow”

puts "wow"

Once a code block has captured everything at a given indentation level then it will expand to capture surrounding indentation.

block = .new(code_lines: code_lines)

.call(block)

block.to_s

=> def dog

  puts "bow"
  puts "wow"
end

Class Method Summary

Instance Method Summary

Constructor Details

.new(code_lines:) ⇒ BlockExpand

[ GitHub ] 

  


# File 'lib/syntax_suggest/block_expand.rb', line 34



def initialize(code_lines:)
  @code_lines = code_lines
end


  







Instance Method Details



  

    #call(block)  
  



  

    

Main interface. Expand current indentation, before expanding to a lower indentation


  



  [ GitHub ]


  

  


# File 'lib/syntax_suggest/block_expand.rb', line 40



def call(block)
  if (next_block = expand_neighbors(block))
    next_block
  else
    expand_indent(block)
  end
end


  








  

    #expand_indent(block)  
  



  

    

Expands code to the next lowest indentation



For example:



1 def dog
2   print "dog"
3 end



If a block starts on line 2 then it has captured all it’s “neighbors” (code at the same indentation or higher). To continue expanding, this block must capture lines one and three which are at a different indentation level.



This method allows fully expanded blocks to decrease their indentation level (so they can expand to capture more code up and down). It does this conservatively as there’s no undo (currently).


  



  [ GitHub ]


  

  


# File 'lib/syntax_suggest/block_expand.rb', line 63



def expand_indent(block)
  now = AroundBlockScan.new(code_lines: @code_lines, block: block)
    .force_add_hidden
    .stop_after_kw
    .scan_adjacent_indent

  now.lookahead_balance_one_line

  now.code_block
end


  








  

    #expand_neighbors(block)  
  



  

    

A neighbor is code that is at or above the current indent line.



First we build a block with all neighbors. If we can’t go further then we decrease the indentation threshold and expand via indentation i.e. #expand_indent



Handles two general cases.



Case #1: Check code inside of methods/classes/etc.



It’s important to note, that not everything in a given indentation level can be parsed as valid code even if it’s part of valid code. For example:



1 hash = {
2   name: "richard",
3   dog: "cinco",
4 }



In this case lines 2 and 3 will be neighbors, but they’re invalid until #expand_indent is called on them.



When we are adding code within a method or class (at the same indentation level), use the empty lines to denote the programmer intended logical chunks. Stop and check each one. For example:



1 def dog
2   print "dog"
3
4   hash = {
5 end



If we did not stop parsing at empty newlines then the block might mistakenly grab all the contents (lines 2, 3, and 4) and report them as being problems, instead of only line 4.



Case #2: Expand/grab other logical blocks



Once the search algorithm has converted all lines into blocks at a given indentation it will then #expand_indent. Once the blocks that generates are expanded as neighbors we then begin seeing neighbors being other logical blocks i.e. a block’s neighbors may be another method or class (something with keywords/ends).



For example:



1 def bark
2
3 end
4
5 def sit
6 end



In this case if lines 4, 5, and 6 are in a block when it tries to expand neighbors it will expand up. If it stops after line 2 or 3 it may cause problems since there’s a valid kw/end pair, but the block will be checked without it.



We try to resolve this edge case with lookahead_balance_one_line below.


  



  [ GitHub ]


  

  


# File 'lib/syntax_suggest/block_expand.rb', line 130



def expand_neighbors(block)
  now = AroundBlockScan.new(code_lines: @code_lines, block: block)

  # Initial scan
  now
    .force_add_hidden
    .stop_after_kw
    .scan_neighbors_not_empty

  # Slurp up empties
  now
    .scan_while { |line| line.empty? }

  # If next line is kw and it will balance us, take it
  expanded_lines = now
    .lookahead_balance_one_line
    .lines

  # Don't allocate a block if it won't be used
  #
  # If nothing was taken, return nil to indicate that status
  # used in `def call` to determine if
  # we need to expand up/out (`expand_indent`)
  if block.lines == expanded_lines
    nil
  else
    CodeBlock.new(lines: expanded_lines)
  end
end


  








  

    #inspect  
  



  

    

Managable rspec errors


  



  [ GitHub ]


  

  


# File 'lib/syntax_suggest/block_expand.rb', line 161



def inspect
  "#<SyntaxSuggest::CodeBlock:0x0000123843lol >"
end