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diff --git a/website/projects/no_excess.html b/website/projects/no_excess.html index 9426e37..873b75e 100644 --- a/website/projects/no_excess.html +++ b/website/projects/no_excess.html @@ -23,4 +23,38 @@ $$START CONTENT <a href="https://git.prestonpan.tech">browse my git frontend</a> for the software names. </p> + +<h2>Explanation</h2> + +<p> + This language was made by separating the interpretation into three phases: the tokenization, the parsing, and the visiting. + The tokenizer takes the input file and groups characters into structures called tokens. This groups characters together in + order to treat things as single objects. For example, the number <i>1582.3</i> should be read as a single number rather than + a string of characters. +</p> + +<p> + The parser was done via recursive descent. Basically, the parser takes the tokens and converts them into abstract syntax tree + nodes. The abstract syntax tree is a hierarchy of data which determines the order of the later execution of the program. + It recursively goes through the tokens, trying to find certain patterns in the tokens and identifying them to be certain + program objects. +</p> + +<p> + During the parsing phase, variables are stored in a hash table and they are set equal to an abstract syntax tree. Later, + this table of global variables will be sent to the visitor to be evaluated. +</p> + +<p> + After the parsing phase is finished, the visitor phase evaluates the abstract syntax tree. It traverses the tree until it + gets to the bottom of it, in which case it returns another abstract syntax tree that corrolates to the value that each node + evaluates to. There are several self evaluating types in this language which return themselves when evaluated, and there + are others that have different rules for what they evaluate to. This is defined in the visitor. +</p> +<p> + When a function is evaluated, each function argument is evaluated as well which is then put on a stack of hash tables. In + this way, I have programmed a simulated stack frame like ones found in C, and recursion is then possible. Symbols in this + language get evaluated to what they are bound to (you can bind symbols to expressions via the `bind` keyword, and local variables + also get evaluated in the same way via the stack frame). +</p> $$END CONTENT |