==== Compilers Exam, 2017-01-20 ====
=== Programming Part ===

The following tasks should be solved in the order below. Write tests for each step!

  * Grade 2: Add new regular expressions to the lexer for each required token of a loop construct of the following form:
    <code>
    for i in 10 .. a+20 do
      write(i);
    done
    </code>
  * Grade 3: Add the new loop construct to the grammar.
  * Grade 4: Change the format of identifiers in the language as follows:
    * Identifiers can contain letters and digits.
    * Letter cannot follow a digit.
  * Grade 5: Extend the semantic analysis:
    * The type of the variable of the for loop must be integer.
    * The type of the lower and upper bound expressions have to be integer.