Class: Lisp::Format::Directives::Print

Inherits:
Directive show all
Defined in:
lib/carat/lisp-format.rb

Overview

Super-class for ‘printing’ directives, namely ~A (Ascii) and ~S (SExpression). These directives print, in some sense, their argument in a Ruby friendly manner. This means that their argument is either converted to a string using Object#to_s or Object#inspect.

Direct Known Subclasses

Ascii, SExpression

Instance Attribute Summary

Attributes inherited from Directive

#pos

Instance Method Summary collapse

Methods inherited from Directive

#join

Constructor Details

#initialize(params, modifiers, top, pos, inspect = false) ⇒ Print

All parameters except inspect are simply passed on to Directive#initialize. If inspect is true, string arguments are inspected as well as all other objects.



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# File 'lib/carat/lisp-format.rb', line 584

def initialize(params, modifiers, top, pos, inspect = false)
  super params, modifiers, top, pos
  @inspect = inspect
end

Instance Method Details

#execute(state) ⇒ Object

Output the given argument as it generally prints in Ruby. The full form is:

~mincol,colinc,minpad,padchar:@[AS]

with the following interpretations

mincol (0)

minimum number of columns to output,

colinc (1)

number of columns to increase by, until mincol is reached,

minpad (0)

minimum amount of padding to add (added before mincol is checked),

padchar (?s)

character to pad with,

:

nil is output as nil (In Lisp, this outputs nil as (), which isn’t generally useful in Ruby. TODO: come up with better use for this modifier),

@

padding is done on the right.



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# File 'lib/carat/lisp-format.rb', line 608

def execute(state)
  padmethod = at_mod? ? :rjust : :ljust
  mincol = param(0, state, 0)
  colinc = param(1, state, 1)
  minpad = param(2, state, 0)
  padchar = param(3, state, ?\s).chr
  arg = state.next_arg
  # XXX: this needs checking use .to_s here?
  str = (arg.is_a? String and not @inspect) ? arg.to_s : arg.inspect
  str = str.send(padmethod, str.length + minpad, padchar)
  k = ((mincol - str.length) / colinc.to_f).ceil
  if k > 0
    str = str.send(padmethod, str.length + colinc * k, padchar)
  end
  state.output str
end