> ELI5: pratt parser How does a computer read math like 3 + 4 × 2? A Pratt Parser teaches the computer which operations are "stronger" (like a referee in a game) You write 3 + 4 × 2 split chopped into pieces (tokens) 3 + 4 × 2 parse result: a tree of operations + 3 × 4 2 compute answer = 11 ✓ × beats + (higher power!) 🧱 Tokens = LEGO Bricks Break the expression into small labeled pieces first. 3 + 4 × 2 numbers & operators Each token knows what it is. The parser reads them one by one. 💪 Binding Power = Grip Each operator has a "grip" strength. Stronger grip grabs numbers first! + grip: weak × grip: strong! × has higher binding power than + so 4 × 2 sticks together first. This is what "precedence" means! 🌳 Parse Tree = Recipe The result is a tree showing what to compute in what order. + 3 × 4 2 ① do this first ② then this eli5.cc

ELI5: pratt parser

high confidence
March 30, 2026
// explanation
// eli5Imagine you're reading a math problem like "2 + 3 × 4". You need to know that multiplication happens before addition. A Pratt parser is like a smart reader that looks at each number and symbol, and figures out which operations to do first by understanding special rules about each symbol [2]. It's simpler than other methods because instead of checking all the rules many times, it just looks at the next symbol and knows what to do [3].

// sources

[1]Simple but Powerful Pratt Parsing - matklad

Apr 13, 2020 ... The simplest technique for hand-writing a parser is recursive descent, which models the grammar as a set of mutually recursive functions.

[2]Pratt Parsers: Expression Parsing Made Easy - Bob Nystrom

Mar 19, 2011 ... Pratt parsing is the jelly. When you mix the two together, you get a simple, terse, readable parser that can handle any grammar you throw at it.

[3]How does Pratt Parsing work? : r/ProgrammingLanguages - Reddit

Feb 9, 2022 ... A Pratt parser dispatches on the next token, instead of recursing down the N precedence levels. In the end it's not all that different.

[4]Operator-precedence parser - Wikipedia

Operator-precedence parser · Contents · Relationship to other parsers · Precedence climbing method · Pratt parsing · Alternative methods · References · External links.

[5]Pratt Parsing - DEV Community

Aug 11, 2017 ... Pratt parsing works by scanning the input tokens, and classifying them into two categories ... operators that operate to the right, with no left- ...

[6]This Simple Algorithm Powers Real Interpreters: Pratt Parsingvideo

Video by Core Dumped

This Simple Algorithm Powers Real Interpreters: Pratt Parsing
[7]Pratt Parsingvideo

Video by Colin James

Pratt Parsing
[8]Parsing Explained - Computerphilevideo

Video by Computerphile

Parsing Explained - Computerphile

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