These three videos are roughly 20 minutes each and cover the three main components of the Eagle Legacy Modernization software, namely the Parser, the Interpreter and the Transformer.
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Parsing takes a source program and a grammar and produces a Programmar Semantic Tree (PST).
A PST is actually a Java Object that contains fields for all the
components of each production rule in the grammar.
The PST is stored as an XML file typically, and becomes a collection of Java objects once it is loaded.
Optionally, the Parser can produce a detailed trace of all the production rules attempted,
including those that did not match.
Duration: ~16 minutes. Automatic Transcript: |
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Interpreting a program generally involves running the program without a compiler or environment.
These interpreters are incomplete but are designed to handle a significant part of each language.
The key to the interpreters as we have implemented them is that all the logic with each statement,
function or operator is kept with the grammar for the language element.
For example, the interpreter for multiplication is in the same file as the grammar production rules.
Duration: ~23 minutes. Automatic Transcript: |
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Generally speaking, Transformation is much more difficult than Interpretation because
most decisions need to be made before running the program.
For this reason, we interpret the program first, and collect metrics to help make those decisions.
Generation is pretty simple for us because we use annotations in the program grammar to control
spaces, line breaks, etc.
Duration: ~23 minutes. Automatic Transcript: |
Last updated: 6/9/2026