This document discusses syntax analysis and parsing. It introduces context-free grammars and how they are used to specify the syntax of programming languages. There are two main types of parsing: top-down parsing which builds the parse tree from the root going down, and bottom-up parsing which builds up the tree from the leaves to the root. Specific parsing algorithms like recursive descent and LR parsing are also introduced.
what is Parsing
different types of parsing
what is parser and role of parser
what is top-down parsing and bottom-up parsing
what is the problem in top-down parsing
design of top-down parsing and bottom-up parsing
examples of top-down parsing and bottom-up parsing
match the following attributes to the parts of a compilerstrips ou.pdfarpitaeron555
match the following attributes to the parts of a compiler
strips out the comments and whitespace
converts text into lexemes
generates an Abstrat Symbol Tree
recursive descent or table driven
uses BNF or EBNF definitions
a. lexer
b. parser
Solution
The Program and Portfolio Management Maturity Model is an effective tool for organizations to
decide quickly what PPM improvements they should make to enhance their organization\'s
ability to optimize investments, execute big changes and deliver value.
Overview
Key Findings
Real project, program and portfolio management, when operating at the level of well-integrated
practices, is the key enabler that allows organizations to identify and execute strategic change.
Any meaningful undertakings to enhance or evolve the program and portfolio management
(PPM) function must pay more than lip service to organizational structure, business model and
culture to have any chance of success.
Competitive pressures and changing market conditions are forcing organizations toward Level 3,
and most organizations still aren\'t ready to make the leap.
Recommendations
At any level of PPM maturity, focus first on helping the organization make well-informed
investment choices. This will improve the odds of project success more than any other factor.
For organizations that require enterprisewide change and capabilities, it is worth the effort to
pursue Level 4, where enterprise PPM practices are built.
Identify objectives for your enterprise, and use them to identify the most salient improvement
opportunities for your enterprise.
Meticulously manage the change involved in maturing/improving your PPM capabilities.
Analysis
Project/program/portfolio management office (PMO) leaders, program managers and portfolio
managers are frequently challenged by ineffective processes, lack of stakeholder engagement and
difficult-to-quantify value. 1 Part of the problem is failure to match their processes, people and
technology approaches to the maturity level of their organizations. 2
The Gartner Program and Portfolio Management (PPM) Maturity Model assessment is designed
to help PPM leaders understand best practices around large project management, as well as PPM
to handle delivery of strategic value. This model assumes that organizations progress through a
maturity curve and that each level of organizational maturity directly affects the level of
investment and types of PPM approaches organizations choose to adopt.
arsing
A parser is an algorithm that determines whether a given input string is in a language and, as a
side-effect, usually produces a parse tree for the input. There is a procedure for generating a
parser from a given context-free grammar.
Recursive-Descent Parsing
Recursive-descent parsing is one of the simplest parsing techniques that is used in practice.
Recursive-descent parsers are also called top-down parsers, since they construct the parse tree
top down (rather than bottom up).
The basic idea of recursive-descent par.
This is the presentation on Syntactic Analysis in NLP.It includes topics like Introduction to parsing, Basic parsing strategies, Top-down parsing, Bottom-up
parsing, Dynamic programming – CYK parser, Issues in basic parsing methods, Earley algorithm, Parsing
using Probabilistic Context Free Grammars.
Overview of Language Processor : Fundamentals of LP , Symbol Table , Data Str...Bhavin Darji
Fundamentals of Language Processor
Analysis Phase
Synthesis Phase
Lexical Analysis
Syntax Analysis
Semantic Analysis
Intermediate Code Generation
Symbol Table
Criteria of Classification of Data Structure of Language Processing
Linear Data Structure
Non-linear Data Structure
Symbol Table Organization
Sequential Search Organization
Binary Search Organization
Hash Table Organization
Allocation Data Structure : Stacks and Heaps
what is Parsing
different types of parsing
what is parser and role of parser
what is top-down parsing and bottom-up parsing
what is the problem in top-down parsing
design of top-down parsing and bottom-up parsing
examples of top-down parsing and bottom-up parsing
match the following attributes to the parts of a compilerstrips ou.pdfarpitaeron555
match the following attributes to the parts of a compiler
strips out the comments and whitespace
converts text into lexemes
generates an Abstrat Symbol Tree
recursive descent or table driven
uses BNF or EBNF definitions
a. lexer
b. parser
Solution
The Program and Portfolio Management Maturity Model is an effective tool for organizations to
decide quickly what PPM improvements they should make to enhance their organization\'s
ability to optimize investments, execute big changes and deliver value.
Overview
Key Findings
Real project, program and portfolio management, when operating at the level of well-integrated
practices, is the key enabler that allows organizations to identify and execute strategic change.
Any meaningful undertakings to enhance or evolve the program and portfolio management
(PPM) function must pay more than lip service to organizational structure, business model and
culture to have any chance of success.
Competitive pressures and changing market conditions are forcing organizations toward Level 3,
and most organizations still aren\'t ready to make the leap.
Recommendations
At any level of PPM maturity, focus first on helping the organization make well-informed
investment choices. This will improve the odds of project success more than any other factor.
For organizations that require enterprisewide change and capabilities, it is worth the effort to
pursue Level 4, where enterprise PPM practices are built.
Identify objectives for your enterprise, and use them to identify the most salient improvement
opportunities for your enterprise.
Meticulously manage the change involved in maturing/improving your PPM capabilities.
Analysis
Project/program/portfolio management office (PMO) leaders, program managers and portfolio
managers are frequently challenged by ineffective processes, lack of stakeholder engagement and
difficult-to-quantify value. 1 Part of the problem is failure to match their processes, people and
technology approaches to the maturity level of their organizations. 2
The Gartner Program and Portfolio Management (PPM) Maturity Model assessment is designed
to help PPM leaders understand best practices around large project management, as well as PPM
to handle delivery of strategic value. This model assumes that organizations progress through a
maturity curve and that each level of organizational maturity directly affects the level of
investment and types of PPM approaches organizations choose to adopt.
arsing
A parser is an algorithm that determines whether a given input string is in a language and, as a
side-effect, usually produces a parse tree for the input. There is a procedure for generating a
parser from a given context-free grammar.
Recursive-Descent Parsing
Recursive-descent parsing is one of the simplest parsing techniques that is used in practice.
Recursive-descent parsers are also called top-down parsers, since they construct the parse tree
top down (rather than bottom up).
The basic idea of recursive-descent par.
This is the presentation on Syntactic Analysis in NLP.It includes topics like Introduction to parsing, Basic parsing strategies, Top-down parsing, Bottom-up
parsing, Dynamic programming – CYK parser, Issues in basic parsing methods, Earley algorithm, Parsing
using Probabilistic Context Free Grammars.
Overview of Language Processor : Fundamentals of LP , Symbol Table , Data Str...Bhavin Darji
Fundamentals of Language Processor
Analysis Phase
Synthesis Phase
Lexical Analysis
Syntax Analysis
Semantic Analysis
Intermediate Code Generation
Symbol Table
Criteria of Classification of Data Structure of Language Processing
Linear Data Structure
Non-linear Data Structure
Symbol Table Organization
Sequential Search Organization
Binary Search Organization
Hash Table Organization
Allocation Data Structure : Stacks and Heaps
White wonder, Work developed by Eva TschoppMansi Shah
White Wonder by Eva Tschopp
A tale about our culture around the use of fertilizers and pesticides visiting small farms around Ahmedabad in Matar and Shilaj.
Hello everyone! I am thrilled to present my latest portfolio on LinkedIn, marking the culmination of my architectural journey thus far. Over the span of five years, I've been fortunate to acquire a wealth of knowledge under the guidance of esteemed professors and industry mentors. From rigorous academic pursuits to practical engagements, each experience has contributed to my growth and refinement as an architecture student. This portfolio not only showcases my projects but also underscores my attention to detail and to innovative architecture as a profession.
Book Formatting: Quality Control Checks for DesignersConfidence Ago
This presentation was made to help designers who work in publishing houses or format books for printing ensure quality.
Quality control is vital to every industry. This is why every department in a company need create a method they use in ensuring quality. This, perhaps, will not only improve the quality of products and bring errors to the barest minimum, but take it to a near perfect finish.
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So, this presentation points designers to some important things that may be missed by an editor that they could eventually discover and call the attention of the editor.
Between Filth and Fortune- Urban Cattle Foraging Realities by Devi S Nair, An...Mansi Shah
This study examines cattle rearing in urban and rural settings, focusing on milk production and consumption. By exploring a case in Ahmedabad, it highlights the challenges and processes in dairy farming across different environments, emphasising the need for sustainable practices and the essential role of milk in daily consumption.
Can AI do good? at 'offtheCanvas' India HCI preludeAlan Dix
Invited talk at 'offtheCanvas' IndiaHCI prelude, 29th June 2024.
https://www.alandix.com/academic/talks/offtheCanvas-IndiaHCI2024/
The world is being changed fundamentally by AI and we are constantly faced with newspaper headlines about its harmful effects. However, there is also the potential to both ameliorate theses harms and use the new abilities of AI to transform society for the good. Can you make the difference?
Dive into the innovative world of smart garages with our insightful presentation, "Exploring the Future of Smart Garages." This comprehensive guide covers the latest advancements in garage technology, including automated systems, smart security features, energy efficiency solutions, and seamless integration with smart home ecosystems. Learn how these technologies are transforming traditional garages into high-tech, efficient spaces that enhance convenience, safety, and sustainability.
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You could be a professional graphic designer and still make mistakes. There is always the possibility of human error. On the other hand if you’re not a designer, the chances of making some common graphic design mistakes are even higher. Because you don’t know what you don’t know. That’s where this blog comes in. To make your job easier and help you create better designs, we have put together a list of common graphic design mistakes that you need to avoid.
3. Introduction
Syntax: the way in which tokens are put together to
form expressions, statements, or blocks of statements.
The rules governing the formation of statements in a
programming language.
Syntax analysis: the task concerned with fitting a
sequence of tokens into a specified syntax.
Parsing: To break a sentence down into its component
parts with an explanation of the form, function, and
syntactical relationship of each part.
The syntax of a programming language is usually given
by the grammar rules of a context free grammar (CFG).
3
5. Introduction…
The syntax analyzer (parser) checks whether a given
source program satisfies the rules implied by a CFG
or not.
If it satisfies, the parser creates the parse tree of that
program.
Otherwise, the parser gives the error messages.
A CFG:
gives a precise syntactic specification of a
programming language.
A grammar can be directly converted in to a parser by
some tools (yacc).
5
6. Introduction…
The parser can be categorized into two groups:
Top-down parser
The parse tree is created top to bottom, starting from
the root to leaves.
Bottom-up parser
The parse tree is created bottom to top, starting from
the leaves to root.
Both top-down and bottom-up parser scan the input
from left to right (one symbol at a time).
Efficient top-down and bottom-up parsers can be
implemented by making use of context-free-
grammar.
LL for top-down parsing
LR for bottom-up parsing
6
7. Context free grammar (CFG)
A context-free grammar is a specification for the
syntactic structure of a programming language.
Context-free grammar has 4-tuples:
G = (T, N, P, S) where
T is a finite set of terminals (a set of tokens)
N is a finite set of non-terminals (syntactic variables)
P is a finite set of productions of the form
A → α where A is non-terminal and
α is a strings of terminals and non-terminals (including the
empty string)
S ∈ N is a designated start symbol (one of the non-
terminal symbols)
7
8. Example: grammar for simple arithmetic
expressions
expression expression + term
expression expression - term
expression term
term term * factor
term term / factor
term factor
factor (expression )
factor id
8
Terminal symbols
id + - * / ( )
Non-terminals
expression
term
Factor
Start symbol
expression
9. Derivation
A derivation is a sequence of replacements of structure names
by choices on the right hand sides of grammar rules.
Example: E → E + E | E – E | E * E | E / E | -E
E → ( E )
E → id
E => E + E means that E + E is derived from E
- we can replace E by E + E
- we have to have a production rule E → E+E in our grammar.
E=>E+E =>id+E=>id+id means that a sequence of replacements of
non-terminal symbols is called a derivation of id+id from E.
9
10. Derivation…
If we always choose the left-most non-terminal in each
derivation step, this derivation is called left-most derivation.
Example: E=>-E=>-(E)=>-(E+E)=>-(id+E)=>-(id+id)
If we always choose the right-most non-terminal in each
derivation step, this derivation is called right-most
derivation.
Example: E=>-E=>-(E)=>-(E+E)=>-(E+id)=>-(id+id)
We will see that the top-down parser try to find the left-most
derivation of the given source program.
We will see that the bottom-up parser try to find right-most
derivation of the given source program in the reverse order.
10
11. Parse tree
A parse tree is a graphical representation of a
derivation.
It filters out the order in which productions are applied
to replace non-terminals.
A parse tree corresponding to a derivation is a labeled
tree in which:
• the interior nodes are labeled by non-terminals,
• the leaf nodes are labeled by terminals, and
• the children of each internal node represent the
replacement of the associated non-terminal in one
step of the derivation.
11
12. 12
Parse tree and Derivation
E E + E | E E | ( E ) | - E | id
Lets examine this derivation:
E -E -(E) -(E + E) -(id + id)
E E
E
-
E
E
-
E
( )
E
E
-
E
( )
+
E E
E
E
-
E
( )
+
E E
id id
This is a top-down derivation
because we start building the
parse tree at the top parse tree
Grammar
13. 13
Which parse tree is correct?
Ambiguity: example
Construct parse tree for the expression: id + id id
E E
+
E E
E
+
E E
E E
E
+
E E
E E
id id
id
E E
E E
E
E E
+
E E
E
E E
+
E E
id id
id
E E + E | E E | ( E ) | - E | id
14. 14
According to the grammar, both are correct.
Ambiguity: example…
Find a derivation for the expression: id + id id
E
+
E E
E E
id id
id
E
*
E E
+
E E
id id
id
A grammar that produces more than one
parse tree for any input sentence is said
to be an ambiguous grammar.
E E + E | E E | ( E ) | - E | id
15. Syntax analysis
Every language has rules that prescribe the syntactic
structure of well formed programs.
The syntax can be described using Context Free
Grammars (CFG) notation.
The use of CFGs has several advantages:
helps in identifying ambiguities
it is possible to have a tool which produces automatically
a parser using the grammar
a properly designed grammar helps in modifying the
parser easily when the language changes
15
16. Top-down parsing
Recursive Descent Parsing (RDP)
This method of top-down parsing can be considered as
an attempt to find the left most derivation for an input
string. It may involve backtracking.
To construct the parse tree using RDP:
we create one node tree consisting of S.
two pointers, one for the tree and one for the input, will
be used to indicate where the parsing process is.
initially, they will be on S and the first input symbol,
respectively.
then we use the first S-production to expand the tree.
The tree pointer will be positioned on the left most
symbol of the newly created sub-tree.
16
17. Bottom up Parsing
Top-down parsers:
• Starts constructing the parse tree at the
top (root) of the tree and move down
towards the leaves.
• Easy to implement by hand, but work
with restricted grammars.
example: predictive parsers
18. 18
Bottom-Up and Top-Down
Parsers
Top-down parsers:
• Starts constructing the parse tree at the top (root) of the
tree and move down towards the leaves.
• Easy to implement by hand, but work with restricted
grammars.
example: predictive parsers
Bottom-up parsers:
• build the nodes on the bottom of the parse tree first.
• Suitable for automatic parser generation, handle a larger
class of grammars.
examples: shift-reduce parser (or LR(k) parsers)
19. 19
Bottom-Up Parser
A bottom-up parser, or a shift-reduce parser, begins
at the leaves and works up to the top of the tree.
The reduction steps trace a rightmost derivation
on reverse.
S aABe
A Abc | b
B d
Consider the Grammar:
We want to parse the input string abbcde.
This parser is known as an LR Parser because
it scans the input from Left to right, and it constructs
a Rightmost derivation in reverse order.
20. Bottom-up parser (LR parsing)
S aABe
A Abc | b
B d
abbcde aAbcde aAde aABe S
At each step, we have to find α such that α is a
substring of the sentence and replace α by A, where
A α
20