Lexically scoped variables in the macro language

[HertzDevil]

The macro interpreter currently does not create lexical scopes for any block parameters. It is up to each block-accepting macro method to define the block variables when a call is interpreted, and these macro methods all leave the variables untouched after that call finishes:

{%
  x = 1
  [2].each { |x| }
  x # => 2
%}

This is inconsistent with blocks in normal code which do create a lexical scope. On the other hand, macro for loops destroy the variables upon exit:

{% begin %}
  {% x = 1 %}
  {% for x in [2] %}
  {% end %}
  {% x %} # Error: undefined macro variable 'x'
{% end %}

for loops don't exist in normal Crystal code, but in Ruby they retain the last values of the variables (and it's a great source of confusion there). IMO both macro constructs should support lexical scoping and the local shadowing of variable names.

[Blacksmoke16]

+1 this has bitten me numerous times.