28
votes
Accepted
Visual programming tools, why don’t they work with the AST directly?
Many of these tools do work directly with the abstract syntax tree (or rather, a direct one-to-one visualisation of it). That includes Blockly, which you've seen, and the other block-based languages ...
- 396
9
votes
Accepted
Is there a correspondence between the syntaxes and the type systems of programming languages?
You seem to have a misunderstanding of the purpose of abstract binding trees (ABTs). They are a tool for describing syntax, much like abstract syntax trees (ASTs). They simply allow you to describe ...
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6
votes
What are the modern alternatives to Backus–Naur form and what are their advantages?
Answer 1: The question is meaningless as written.
You are mixing different kinds of notations here that are intended for different purposes.
BNF and ABNF are concrete notations for writing the ...
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6
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Visual programming tools, why don’t they work with the AST directly?
At least two reasons:
Because source code is a much more concise representation. Laying out an AST as a graph would take up a lot more visual real estate.
Programmers prize having as much context ...
D.W.♦
- 164k
4
votes
Accepted
Simple example for Higher Order Abstract Syntax (λ-tree syntax)
Well, this is a bit broad but the basic idea is the following. In First-order abstract syntax (FOAS) we model lambda terms following their syntax tree. E.g., in Coq we would write
...
- 14.6k
4
votes
Accepted
How do I interpret the wording of this passage about abstract binding trees from the book Practical Foundations of Programming Languages
Just to clear something up that may not have been obvious, $\chi$ is a set and the notation $B[\chi, x]$ is meant to be ABTs under free variables that are either $x$ or are in $\chi$. In this notation ...
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3
votes
Accepted
Code optimization - syntax tree vs. intermediate representation
These days, the trend is to do optimization with the intermediate representation. Check out LLVM for example:
The LLVM Core libraries provide a modern source- and target-independent optimizer, along ...
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3
votes
What are the modern alternatives to Backus–Naur form and what are their advantages?
Here are a couple of pertinent references which support the idea "It mostly doesn't matter/write your own":
different parsing approaches: https://code.jsoftware.com/wiki/Guides/Parsing
a ...
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3
votes
What are the known ambiguities in C language grammar?
Not sure if this answers your question, but I will contribute two details regarding lexing/parsing ambiguities in C in general. I hope these are still helpful.
Consider the expression ...
3
votes
Visual programming tools, why don’t they work with the AST directly?
The typical AST by compilers is rather complex and verbose. The directed graph representation would quickly become quite hard to follow. But there are two large areas of CS where ASTs are used.
...
- 381
2
votes
Accepted
Where does LL parser belong in the top-down parsers classification
First let's make some general remarks about nomenclature. They are not all relevant here, but they may help you in the future.
not all authors are using the same precise definition. Sometimes the ...
- 3,109
2
votes
Accepted
Neither Left nor Rightmost Derivations
The main reason is that context-free grammars, once introduced, were quickly adapted to provide a theoretical basis for program language compilation. For this usage, the goal is to parse as quickly ...
- 36
1
vote
find maximum in arbitrary expression tree
The general solution is to use symbolic execution.
Let me start by explaining how to solve this if you have straight-line code, with no conditional statements (no if's). First, for each program ...
D.W.♦
- 164k
1
vote
Textbook on formal syntax (and semantics) of programming languages
The book Practical Foundations for Programming Languages might have what you're looking for.
An older version of the book can be read here.
- 131
1
vote
Textbook on formal syntax (and semantics) of programming languages
Maybe you will like to book Concrete Semantics (which is freely available as a PDF). It defines the syntax and semantics of an imperative programming language using the proof assistant Isabelle/HOL. ...
- 131
1
vote
How many syntax trees can be made by a BNF
The answer is given by the Catalan numbers; if you have $n$ operators, the number of syntax trees is $\frac{1}{n+1}{2n \choose n}$. The problem is equivalent to finding all ways of inserting $n$ ...
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The origin and the meaning of "Abstract Syntax Tree"
You are asking three questions. I will answer one.
I don't think "abstract syntax tree" is a misnomer. It aims to represent the syntax of the expression. It is not claimed to represent all of the ...
D.W.♦
- 164k
1
vote
How to generate (Java) source code in academically acceptable way - using abstract syntax tree?
It highly depends on what is the domain you are working on, i.e. why do you need to generate Java Source code anyway?.
Can you explain better what knowledge do you have stored in your knowledge base?....
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