In which we interpret Forth using Forth and a bit of cheating With an implementation of refill, we are in the position of implementing the interpreter loop in Forth itself. In the previous post, we defined the interpreter loop like this: attempt to read a line into the input buffer while last read was successful … Continue reading Forth interpreting Itself
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Forth Inside Out part 2
In which we internalise the read-execute loop, or die in the attempt. In Forth: Inside Out I did some refactoring on the read-execute loop. In this part I and going to re-engineer it entirely and implement it in Forth. The reason for doing this is that it will play better with some of the core … Continue reading Forth Inside Out part 2
Forth: Inside Out
In which we turn the interpreter inside out My Forth interpreter is working fairly well so far, but I think there is some unnecessary complexity. The interpreter is event driven, which means that everything it does is driven by some event, which is always receipt of some text input. This works OK and I chose … Continue reading Forth: Inside Out
State of the Blog and Future Ideas
It's the end of summer, 2021. It's some time since I have posted anything, mainly because, this year things like music festivals have been allowed to take place in the UK, so I've been taking advantage of them instead of sitting in front of my computer writing material for this blog. I'd like to apologise, … Continue reading State of the Blog and Future Ideas
Signal Handling in Swift
For my series of posts on the Lambda Calculus, I have developed a lambda calculator. At the time of writing, it only works in "single step mode": you hit the return key having typed in a lambda expression and it does one beta reduction. Hit the return key again and it does another beta reduction. … Continue reading Signal Handling in Swift
Protocol OrientedProgramming part 2
This post is all about how I achieved stage 1 of the conversion of the Lambda Calculator. It follows on from Protocol Oriented Programming. I have commented out all of the code in Expression.swift and added a protocol Expressible. All the functions that were "abstract" in Expression become protocol requirements and all of the functions … Continue reading Protocol OrientedProgramming part 2
Protocol Oriented Programming
This is technically a post in the Lambda Calculus series but I am concerned with the implementation of my Lambda calculator today. Anybody who has looked at the code will see I have used a class hierarchy to represent Lambda expressions. I use classes because I want my objects to be of reference types so … Continue reading Protocol Oriented Programming
Numbers in The Lambda Calculus
God created the natural numbers. All else is the work of man.Leopold Kronecker We've got lists and with lists we can do pretty much any data structure we like. However, in computing, we also need numbers. Usually, numbers are thought of as fairly basic entities with respect to computing, but, in the Lambda Calculus they … Continue reading Numbers in The Lambda Calculus
Lambda Calculus: Recursion
"When preceded by its quotation yields falsehood" when preceded by its quotation yields falsehood.Willard Van Orman Quine Before we start, recursion is a tricky subject. I suggest you read this article before continuing. Also, you're going to need at least version 1.3.1 of the lambda calculator to try out the examples. This version allows variable … Continue reading Lambda Calculus: Recursion
Lists in the Lambda Calculus
Some Lambda Calculator Enhancements In version 1.2.1 of the Lambda Calculator, I have added the concept of a meta command. A meta command starts with a / (forward slash) and is used for doing things outside of the Lambda Calculus (forward slash is sort of the opposite of backslash, which is my alternate way of … Continue reading Lists in the Lambda Calculus
Sincere Flattery 