Class: XRB::Location

Inherits:
Object
  • Object
show all
Defined in:
lib/xrb/error.rb

Overview

A byte offset resolved to a line within an input string.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input, offset) ⇒ Location

Initialize a location for a byte offset within an input string.

Raises:

  • (ArgumentError) 


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# File 'lib/xrb/error.rb', line 48

def initialize(input, offset)
  raise ArgumentError.new("Offset #{index} is past end of input #{input.bytesize}") if offset > input.bytesize
  
  @offset = offset
  @line_index = 0
  line_offset = next_line_offset = 0
  
  input.each_line do |line|
    line_offset = next_line_offset
    next_line_offset += line.bytesize
    
    # Is our input offset within this line?
    if next_line_offset >= offset
      @line_text = line.chomp
      @line_range = line_offset...next_line_offset
      break
    else
      @line_index += 1
    end
  end
end

Instance Attribute Details

#line_index ⇒ Object (readonly)

The line that contains the @offset (base 0 indexing).



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# File 'lib/xrb/error.rb', line 83

def line_index
  @line_index
end

#line_range ⇒ Object (readonly)

The byte offset to the start of that line.



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# File 'lib/xrb/error.rb', line 91

def line_range
  @line_range
end

#line_text ⇒ Object (readonly)

Returns the value of attribute line_text.



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# File 'lib/xrb/error.rb', line 98

def line_text
  @line_text
end

Instance Method Details

#line_number ⇒ Object

The line index, but base-1.



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# File 'lib/xrb/error.rb', line 86

def line_number
  @line_index + 1
end

#line_offset ⇒ Object

The number of bytes from the start of the line to the given offset in the input.



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# File 'lib/xrb/error.rb', line 94

def line_offset
  @offset - @line_range.min
end

#to_i ⇒ Object

Convert the location to its absolute byte offset.



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# File 'lib/xrb/error.rb', line 72

def to_i
  @offset
end

#to_s ⇒ Object

Format the location as a one-based line number and zero-based line offset.



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# File 'lib/xrb/error.rb', line 78

def to_s
  "[#{self.line_number}:#{self.line_offset}]"
end