Some language environments provide an interactive interface called a Read-Eval-Print-Loop (abbreviated REPL). One key characteristic of a REPL is the ability to incrementally define, extend and re-define your environment. This is particularly challenging in a pure-functional context, such as the evaluator we have developed so far. Modularity and incremental development seems to imply the need […]
25
Oct
2010
Evaluating Expressions, part 5 – Recursion
Tags: actor, data-flow, equation, evaluation, imperative, language, pattern-matching, protocol, recursion, synchronization, unification, value
10
Oct
2010
Evaluating Expressions, part 4 – Pattern Equations
Tags: actor, equality, equation, evaluation, identity, language, pair, pattern-matching, protocol, unification, value
In part 4 of our series implementing programming language constructs with actors, we extend our pattern matching behaviors to support pattern equations. These are true equations that express relationships between patterns. They form the basis for introducing LET and IF expressions. The grammar for our extended language is shown below. Changes from part 3 are […]