Formal languages

Parsing expression grammar

In computer science, a parsing expression grammar (PEG) is a type of analytic formal grammar, i.e. it describes a formal language in terms of a set of rules for recognizing strings in the language. The formalism was introduced by Bryan Ford in 2004 and is closely related to the family of top-down parsing languages introduced in the early 1970s.Syntactically, PEGs also look similar to context-free grammars (CFGs), but they have a different interpretation: the choice operator selects the first match in PEG, while it is ambiguous in CFG. This is closer to how string recognition tends to be done in practice, e.g. by a recursive descent parser. Unlike CFGs, PEGs cannot be ambiguous; if a string parses, it has exactly one valid parse tree. It is conjectured that there exist context-free languages that cannot be recognized by a PEG, but this is not yet proven. PEGs are well-suited to parsing computer languages (and artificial human languages such as Lojban), but not natural languages where the performance of PEG algorithms is comparable to general CFG algorithms such as the Earley algorithm. (Wikipedia).

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Verbal Expressions Basics 3

In this video we look at translating a verbal expression to an algebraic one.

From playlist Algebra 1 Test 1

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Multiplying rational expressions

Learn how to multiply rational expressions. A rational expression is an expression in the form of a fraction where the numerator and/or the denominator are/is an algebraic expression. To multiply two rational expressions, we use the distributive property to multiply both numerators togethe

From playlist Multiply Rational Expressions (Binomials) #Rational

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Evaluating mathematical expressions

๐Ÿ‘‰ Learn how to evaluate mathematics expressions. A mathematics expression is a finite combination of numbers and symbols formed following a set of operations or rules. To evaluate a mathematics expression means to obtain the solution to the expression given the value(s) of the variable(s)

From playlist Simplify Expressions Using Order of Operations

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I still don't get it evaluating expressions

๐Ÿ‘‰ Learn how to evaluate mathematics expressions. A mathematics expression is a finite combination of numbers and symbols formed following a set of operations or rules. To evaluate a mathematics expression means to obtain the solution to the expression given the value(s) of the variable(s)

From playlist Simplify Expressions Using Order of Operations

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Evaluating a rational expression and order of operations

๐Ÿ‘‰ Learn how to evaluate mathematics expressions. A mathematics expression is a finite combination of numbers and symbols formed following a set of operations or rules. To evaluate a mathematics expression means to obtain the solution to the expression given the value(s) of the variable(s)

From playlist Simplify Expressions Using Order of Operations

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Evaluate an expression with three variables

๐Ÿ‘‰ Learn how to evaluate mathematics expressions. A mathematics expression is a finite combination of numbers and symbols formed following a set of operations or rules. To evaluate a mathematics expression means to obtain the solution to the expression given the value(s) of the variable(s)

From playlist Simplify Expressions Using Order of Operations

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Ruby Conference 2007 Treetop: Syntactic Analysis with Ruby by Nathan Sobo

Help us caption & translate this video! http://amara.org/v/FGd9/

From playlist Ruby Conference 2007

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Parsing with Derivatives

(February 9, 2011) Matthew Might focuses on a new way to write parsers and how it will affect computer science in the future. Might discusses these parsers and overall language theory, to help explain how there is demand for better parsing tools and how computer science will be improved in

From playlist Engineering

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Evaluate an equation by substitution

๐Ÿ‘‰ Learn how to evaluate mathematics expressions. A mathematics expression is a finite combination of numbers and symbols formed following a set of operations or rules. To evaluate a mathematics expression means to obtain the solution to the expression given the value(s) of the variable(s)

From playlist Simplify Expressions Using Order of Operations

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RubyConf 2010 - Grammars, Parsers, and Interpreters, In Ruby by: Michael J. I. Jackson

Parsing expression grammars (PEG) are a declarative alternative to the traditional generative approach of context-free grammars (CFG) and regular expressions. They require no tokenization phase, and are usually simpler to understand and maintain. We'll be discussing the Citrus and Treetop

From playlist RubyConf 2010

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Ruby on Ales 2015 - Time flies like an arrow, fruit flies like a banana by Hsing-Hui Hsu

How do we make sense of a regular sentence, especially when they take us down the "garden path"? For example, when we see a sentence that starts with "The old man," most of us would expect the next word to be a verb. So when we read, "The old man the boat," we have to backtrack to re-evalu

From playlist Ruby on Ales 2015

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RubyConf 2015 - Time flies like an arrow; Fruit flies like a banana... by Hsing-Hui Hsu

Time flies like an arrow; Fruit flies like a banana: Parsers for Great Good by Hsing-Hui Hsu When you type print "Hello, world!", how does your computer know what to do? Humans are able to naturally parse spoken language by analyzing the role and meaning of each word in context of its sen

From playlist RubyConf 2015

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LoneStarRuby Conf 2008 - Grammar a BNF like Ruby DSL Parsing 960x368 by: Eric Mahurin

Grammar a BNF like Ruby DSL Parsing 960x368 by: Eric Mahurin Help us caption & translate this video! http://amara.org/v/G13L/

From playlist Lone Star Ruby Conference 2008

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Evaluating an expression with one variable ex 7, w^2 - 3w + 10; w = 4

๐Ÿ‘‰ Learn how to evaluate mathematics expressions. A mathematics expression is a finite combination of numbers and symbols formed following a set of operations or rules. To evaluate a mathematics expression means to obtain the solution to the expression given the value(s) of the variable(s)

From playlist Simplify Expressions Using Order of Operations

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Writing a PEG Parser For Fun and Profit

Parsing Expression Grammars (PEGs) are a relatively new formalism for describing grammars suitable for automatically generating efficient parsers. I've become interested in using a PEG-generated parser as an alternative to CPython's nearly 30 year old "pgen" parser generator. This poses so

From playlist Python

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ElixirConf 2015 - The road to intellij-elixir 1.0.0 By Luke Imhoff

Learn how naively copying a grammar file from one parser generator to another won't work. Go back to the beginning and learn about lexers vs parsers, but discover that the power of interpolation changes the computational complexity and forces the lexer to be a push-down automata instead of

From playlist ElixirConf 2015

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Parser and Lexer โ€” How to Create a Compiler part 1/5 โ€” Converting text into an Abstract Syntax Tree

In this tool-assisted education video I create a parser in C++ for a B-like programming language using GNU Bison. For the lexicographical analysis, a lexer is generated using re2c. This is part of a multi-episode series. In the next video, we will focus on optimization. Become a member:

From playlist Creating a Compiler

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Using order of operations to simplify an expression - Online Tutor

๐Ÿ‘‰ Learn how to simplify mathematics expressions. A mathematis expression is a finite combination of numbers and symbols formed following a set of operations or rules. To simplify a mathematics expression means to reduce the expression into simpler form. For expressions having parenthesis

From playlist Simplify Expressions Using Order of Operations

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How to simplify an expression by following order of operations and distributive property

๐Ÿ‘‰ Learn how to simplify mathematics expressions. A mathematis expression is a finite combination of numbers and symbols formed following a set of operations or rules. To simplify a mathematics expression means to reduce the expression into simpler form. For expressions having parenthesis

From playlist Simplify Expressions Using Order of Operations

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Monadic Parsers at the Input Boundary

When reading a byte stream over the process I/O boundary, the first thing which everyone should do is to parse the byte stream with a monadic parser. The talk will discuss Processes and input byte streams. Monadic parsers. What they are and why they matter. The design and use of the pure

From playlist Functional Programming

Related pages

Parser combinator | Syntactic predicate | Context-free language | GLR parser | Ambiguous grammar | Recursive descent parser | Parsing | Top-down parsing language | Logic programming | Mutual recursion | Context-free grammar | Floydโ€“Warshall algorithm | Disjoint sets | Formal grammar | Dangling else | Comparison of parser generators | Exponential time | LL parser | Formal language | Parse tree | Greedy algorithm | Left recursion | Compiler Description Language | Bellmanโ€“Ford algorithm | Regular expression | Expression (mathematics) | Cut (logic programming) | Function (mathematics) | Backtracking | Boolean grammar | LR parser | CYK algorithm | Recursion | String (computer science)