Abstract Syntax Tree (AST)

An Abstract Syntax Tree for a code snippet C is a tuple ⟨N ,T , X , f, d, l⟩ where

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• N is a set of nonterminal nodes,
• T is a set of terminal nodes,
• X is a set of values,
• f ∈ N is the root node,
• d : N → (N ∪ T) is a function that maps a nonterminal node to a list of its children,
• l : T → X is a function that maps a terminal node to an associated value.

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Every node except the root appears exactly once in all the lists of children.

Example of representation of Java function which finds object in array as AST

https://docs.python.org/3/library/ast.html

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FastAI

FastAI is a deep learning library which provides practitioners with high-level components that can quickly and easily provide state-of-the-art results in standard deep learning domains, and provides researchers with low-level components that can be mixed and matched to build new approaches. It aims to do both things without substantial compromises in ease of use, flexibility, or performance.

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https://docs.fast.ai/

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Representation of Code snippet as set of triplets

Given a code snippet C and its AST ⟨N,T,X,s, δ, ϕ⟩, we denote by T Pairs the set of all pairs of AST terminal nodes (excluding pairs that contain a node and itself):

That is, C is represented as the set of triplets ⟨xs , p, xt⟩ such that xs and xt are values of AST terminals, and p is the AST path that connects them.

FastAI basics

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