eplmediawiki - User contributions [en]

Main Page

2013-02-27T19:54:41Z

Admin:

It is our purpose to provide ''theoretical'' and ''practical support'' to those who want to '''design and process formal programming languages''' (both general purpose or domain specific).

So we gathered in this site information about Grammars (for different Languages) and Tools (like ''compiler generators'') for Language Processing.
The ''basic concepts'' in the area of Language Processing are identified and defined.
Also information about Virtual Machines (that are becoming more and more important as the target for compilers) is provided.

== Categories ==
[[Image:b_bc.png|link=Category:Basic Concepts]]
   
[[Image:b_lg.png|link=Category:Languages and Grammars]]
 
[[Image:b_cg.png|link=Category:Compiler Generators]]
   
[[Image:b_vm.png|link=Category:Virtual Machines]]
 
[[Image:b_tu.png|link=Category:Tools & Utilities]]
 

== Map of Concepts ==
Click on the image to get access to the map.
[[File:Map.jpg|1000px|link=http://eplmediawiki.di.uminho.pt/Map.html]]

Grammar

2013-02-27T19:39:51Z

Admin:

Formally, a '''grammar''' is an ordered fourtuple ''G'' = (''T,N,S,P''), where ''N'' and ''T'' are finite alphabets, ''S'' is a distinguished symbol of ''N'', and ''P'' is a finite non-empty set pairs (L,R) such that ''L'' and ''R'' are in (''N U T'')* and ''G'' is called a '''Context Free Grammar''' (CFG) if ''L'' is in ''N''.
 

The symbols of ''N'' are called ''nonterminal symbols''. The symbols of ''T'' are called ''terminal symbols''. According to above definition of a grammar ''G'', the sets ''N'' and ''T'' are disjoint in every grammar. The nonterminal symbol ''S'' is called the initial symbol, axiom or root, and is used to start the derivations of the sentences of the language.
 

The ordered pairs in ''P'' are called ''rewriting rules'' or ''productions'' and will be written in the form L ---> R where the symbol ---> (derives) is, of course, not in ''N U T''. Productions are used to derive new sentences from given ones by replacing a part equal to the left-hand side of a rule by the right-hand side of the same rule.
 

In such a way, taking always ''S'' as the starting symbol, it is possible to derive from ''S'' and just applying productions in ''P'', a set (possibly infinite) of sentences that is called the language generated by ''G'', ''L(G)''.
 

'''See following grammar example:''' [http://eplmediawiki.di.uminho.pt/uploads/NLPDgrammar.pdf nLPD grammar]

[[Category: Basic Concepts]]

File:NLPDgrammar.pdf

2013-02-27T19:39:09Z

Admin:

Category:Tools & Utilities

2013-01-09T10:53:05Z

Admin: Protected "Category:Tools & Utilities" (‎[edit=sysop] (indefinite) ‎[move=sysop] (indefinite))

This category groups a set of pages that contain information about Tools that help on the development and analysis of Grammars or Regular Expressions.

Other environments or tools useful for various activities (like planning, editing, reporting, etc.) involved in the development of a project are also included here.

_________________________________________________________

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

_________________________________________________________

Category:Virtual Machines

2013-01-05T18:02:19Z

Admin: atualização do texto introdutório desta categoria

The pages grouped under this category provide information about Virtual Machines used in academic or professional environments as the target of some compilers.

A Virtual Machine (VM) is a program that simulates the behavior of a real CPU.

The program uses data structures to implement the blocks that compose the machine architecture like the ''decoder'',
the ''controller'', the ''registers'', the ''stack'', the ''data'' and ''program memories'', the ''input/output ports'', etc.

It accepts as input a ''list of instructions'' (the machine code), written in the style of an Assembly language (operator followed by zero or
more operands), and interprets (recognizes and
executes) them sequentially from the first to the last or until finding one that halts the execution.

In this way, the VM simulates the execution of the program (defined by that list of instructions) on a real CPU.

The biggest advantage of using a VM as the target of a Compiler is the possibility to run a program independently of the hardware.
The most famous example is JVM, Java Virtual Machine, used by the Java Compiler -- in this way the same java byte-code can be executed in any hardware platform where a JVM is installed.

_________________________________________________________

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

_________________________________________________________

Category:Basic Concepts

2013-01-05T17:02:44Z

Admin: creation of the introductory text for this category

This category gathers definitions related to the ''basic concepts'' underlying the area of Language Processing (LP).

It is organized in a dictionary style in order to enable a simple and quick consult.

_________________________________________________________

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

_________________________________________________________

Category:Tools & Utilities

2013-01-05T16:53:52Z

Admin:

Category:Tools & Utilities

2013-01-05T16:49:15Z

Admin: creation of the introductory text for this category

This category groups a set of pages that contain information about Tools that help on the development and analysis of Grammars or Regular Expressions.

_________________________________________________________

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

_________________________________________________________

Category:Virtual Machines

2013-01-05T16:37:35Z

Admin: creation of the introductory text for this category

The pages grouped under this category provide information about Virtual Machines used in academic or professional environments as the target of some compilers.

_________________________________________________________

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

_________________________________________________________

Category:Languages and Grammars

2013-01-05T16:32:43Z

Admin:

In this category we collect information about Programming Languages: their Characteristics (purpose, underlying philosophy and usage); and Grammars.

At moment this page is under construction....

_________________________________________________________

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

_________________________________________________________

Category:Compiler Generators

2013-01-05T16:24:53Z

Admin:

A Compiler Generator (CG) is a program that takes, as input, a Language Specification (a Regular Expression (ER), a Grammar (G), etc.) and produces, as output, another program that is a Processor (a Compiler, an Interpreter, or whatever) for the language specified.

Notice that the correct name for this special program should be Language-Processor Generator.
However the actual name is indeed Compiler Generator; alternatively, it is
also known as Compilers Compiler.

The usefulness of such a program is unquestionable.
From a short and concise formal specification of a language, a complex and efficient
program is quickly generated with the guarantee that the generated program will recognize all the valid sentences
that belong to that language and will transform/translate them in a systematic way.

From a large list of well known Compiler Generators---Yacc, Btyacc, Mlyacc, Happy, Coco/R, Tools, CTB, JavaCC, CUP, LISA, Eli, PCCTS, AnTLR, Silver, Sable, SGen, LRC, ASF+SDF---we chose a subset of them to install and test.

The pages in this category correspond, precisely, to the selected Compiler Generators and provide some pratical information about each one.

To enable the comparasion of each tool usage,
all of the CG chosen were experimented with the same language, ''Lavanda'',
that is a didatic Domain Specific Language designed for teaching purposes.
''Lavanda'' is specified by the following grammar:
[http://eplmediawiki.di.uminho.pt/uploads/Lavanda.pdf LavandaGrammar].

A small set of input texts, to test the compiler generated by each tool, is available [http://eplmediawiki.di.uminho.pt/uploads/SamplesLavanda.zip here].

An article comparing three compiler generators (Lex/Yacc, LISA and ANTLR-3) ca be found [http://eplmediawiki.di.uminho.pt/uploads/CoRTA07CGvs.pdf here].

_________________________________________________________

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

_________________________________________________________

Category:Compiler Generators

2013-01-05T01:23:36Z

Admin:

A Compiler Generator (CG) is a program that takes, as input, a Language Specification (a Regular Expression (ER), a Grammar (G), etc.) and produces, as output, another program that is a Processor (a Compiler, an Interpreter, or whatever) for the language specified.

Notice that the correct name for this special program should be Language-Processor Generator.
However the actual name is indeed Compiler Generator; alternatively, it is
also known as Compilers Compiler.

The usefulness of such a program is unquestionable.
From a short and concise formal specification of a language, a complex and efficient
program is quickly generated with the guarantee that the generated program will recognize all the valid sentences
that belong to that language and will transform/translate them in a systematic way.

From a large list of well known Compiler Generators---Yacc, Btyacc, Mlyacc, Happy, Coco/R, CTB, Tools, JavaCC, CUP, SGen, LRC,
LISA, Eli, PCCTS, AnTLR, Silver, Sable, ASF+SDF---we chose a subset of them to install and test.

To enable the comparasion of each tool usage,
all of the CG chosen were experimented with the same language, Lavanda,
that is a didatic Domain Specific Language used for teaching purposes.
Lavanda is specified by the following grammar:
[http://eplmediawiki.di.uminho.pt/uploads/Lavanda.pdf LavandaGrammar].

A small set of input texts, to test the compiler generated by each tool, is available [http://eplmediawiki.di.uminho.pt/uploads/SamplesLavanda.zip here].

An article comparing three compiler generators (Lex/Yacc, LISA and ANTLR-3) ca be found [http://eplmediawiki.di.uminho.pt/uploads/CoRTA07CGvs.pdf here].

_________________________________________________________

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

_________________________________________________________

Category:Compiler Generators

2013-01-05T01:18:45Z

Admin: atualização do texto introdutório desta categoria

A Compiler Generator (CG) is a program that takes, as input, a Language Specification (a Regular Expression (ER), a Grammar (G), etc.) and produces, as output, another program that is a Processor (a Compiler, an Interpreter, or whatever) for the language specified.

Notice that the correct name for this special program should be Language-Processor Generator.
However the actual name is indeed Compiler Generator; alternatively, it is
also known as Compilers Compiler.

The usefulness of such a program is unquestionable.
From a short and concise formal specification of a language, a complex and efficient
program is quickly generated with the guarantee that the generated program will recognize all the valid sentences
that belong to that language and will transform/translate them in a systematic way.

From a large list of well known Compiler Generators---Yacc, Btyacc, Mlyacc, Happy, Coco/R, CTB, Tools, JavaCC, CUP, SGen, LRC,
LISA, Eli, PCCTS, AnTLR, Silver, Sable, ASF+SDF---we chose a subset of them to install and test.
To enable the comparasion of the usage of each tool,
all of the CG chosen were experimented with the same language, Lavanda,
that is a didatic Domain Specific Language used for teaching purposes.
Lavanda is specified by the following grammar:
[http://eplmediawiki.di.uminho.pt/uploads/Lavanda.pdf LavandaGrammar].

A small set of input texts, to test the compiler generated by each tool, is available [http://eplmediawiki.di.uminho.pt/uploads/SamplesLavanda.zip here].

An article comparing three compiler generators (Lex/Yacc, LISA and ANTLR-3) ca be found [http://eplmediawiki.di.uminho.pt/uploads/CoRTA07CGvs.pdf here].

_________________________________________________________
Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

Category:Languages and Grammars

2013-01-03T01:07:22Z

Admin:

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

In this category we collect information about Programming Languages: their Characteristics (purpose, underlying philosophy and usage); and Grammars.

At moment this page is under construction....

Category:Languages and Grammars

2013-01-03T01:00:01Z

Admin: criação do texto base desta categoria

In this category we collect information about Programming Languages: their Characteristics (purpose, underlying philosophy and usage); and Grammars.

At moment this page is under construction....

Main Page

2013-01-03T00:36:01Z

Admin: revisão do texto introdutório da Homepage

Main Page

2013-01-03T00:30:53Z

Admin:

It is our purpose to provide ''theoretical'' and ''practical support'' to those who want to '''design and process formal programming languages''' (both general purpose or domain specific).

So we gathered in this site information about Grammars (for different Languages) and Tools (like ''compiler generators'') for Language Processing.
The basic concepts in the area of Language Processing are identified and defined.
Also information about Virtual Machines (that are becoming more and more important as the target for compilers) is provided.

== Categories ==
[[Image:b_bc.png|link=Category:Basic Concepts]]
   
[[Image:b_lg.png|link=Category:Languages and Grammars]]
 
[[Image:b_cg.png|link=Category:Compiler Generators]]
   
[[Image:b_vm.png|link=Category:Virtual Machines]]
 
[[Image:b_tu.png|link=Category:Tools & Utilities]]
 

== Map of Concepts ==
Click on the image to get access to the map.
[[File:Map.jpg|1000px|link=http://eplmediawiki.di.uminho.pt/map.html]]

Main Page

2013-01-03T00:17:38Z

Admin:

It is our purpose to provide ''theoretical'' and ''practical support'' to those who want to '''design and process formal programming languages''' (both general purpose or domain specific).

So we gathered in this site information about Grammars (for different Languages) and Tools (like compiler generators) for Language Processing.
The basic concepts in the area of Language Processing are identified and defined.
Also information about Virtual Machines (that are becoming more and more important as the target for compilers) is provided.

== Categories ==
[[Image:b_bc.png|link=Category:Basic Concepts]]
   
[[Image:b_lg.png|link=Category:Languages and Grammars]]
 
[[Image:b_cg.png|link=Category:Compiler Generators]]
   
[[Image:b_vm.png|link=Category:Virtual Machines]]
 
[[Image:b_tu.png|link=Category:Tools & Utilities]]
 

== Map of Concepts ==
Click on the image to get access to the map.
[[File:Map.jpg|1000px|link=http://eplmediawiki.di.uminho.pt/map.html]]

Main Page

2013-01-03T00:14:40Z

Admin:

It is our purpose to provide theoretical and practical support to those who want to design and process formal (programming or domain specific) languages.

So we gathered in this site information about Grammars (for different Languages) and Tools (like compiler generators) for Language Processing.
The basic concepts in the area of Language Processing are identified and defined.
Also information about Virtual Machines (that are becoming more and more important as the target for compilers) is provided.

== Categories ==
[[Image:b_bc.png|link=Category:Basic Concepts]]
   
[[Image:b_lg.png|link=Category:Languages and Grammars]]
 
[[Image:b_cg.png|link=Category:Compiler Generators]]
   
[[Image:b_vm.png|link=Category:Virtual Machines]]
 
[[Image:b_tu.png|link=Category:Tools & Utilities]]
 

== Map of Concepts ==
Click on the image to get access to the map.
[[File:Map.jpg|1000px|link=http://eplmediawiki.di.uminho.pt/map.html]]

LALR Parsers

2012-12-27T22:41:20Z

Admin:

'''''LALR''' - '''L'''ook '''A'''head '''L'''eft-to-right parse, '''R'''ightmost-derivation''.
 

LALR parsers are a specialized form of [http://eplmediawiki.di.uminho.pt/index.php/LL(k)_----_LL(1)_Parsers LR parsers] that can deal with more context-free grammars than Simple LR parsers [INSERIR LINKS] but less than [http://eplmediawiki.di.uminho.pt/index.php/LL(k)_----_LL(1)_Parsers LR(1)] parsers can.
 

LALR parsers were introduced as practical parsers for deterministic languages. Rather than building an exponential number of LR(k) states, LALR(k) parsers add lookahead sets to the actions of the small LR(0) parser. While SLR uses follow sets to construct reduce actions, LALR uses lookahead sets, which are more specific because they take more of the parsing context into account.
 

In LR(1) parsing, an item '''A ::= a''' (s1) is different from '''A ::= a''' (s2) if s1 is different from s2. This results to a large number of states since the combinations of expected lookahead symbols can be very large. To reduce the number of states, when we have two items like those two, instead of creating two states (one for each item), we combine the two states into one by creating an item '''A := a''' (s3) where s3 is the union of s1 and s2. Since we make the expected lookahead sets larger, there is a danger that some conflicts will have worse chances to be resolved. But the number of states we get is the same as that for LR(0). This grammar is called LALR(1).
 

== LALR parser generators ==
# [http://www.parsifalsoft.com/ AnaGram]
# [http://beaver.sourceforge.net/ BEAVER]
# [http://www.cs.princeton.edu/~appel/modern/java/CUP CUP]
# ELI
# [http://www.devincook.com/goldparser/ Gold]
# [http://www.hwaci.com/sw/lemon/ Lemon]
# [http://eplmediawiki.di.uminho.pt/index.php/Lisa LISA]
# [http://www.mathematik.uni-ulm.de/modula Ulm's Modula-2 System]
# [http://eplmediawiki.di.uminho.pt/index.php/Yacc YACC]
# [http://www.gradsoft.com.ua/products/yayacc_eng.html YaYacc]

[[Category:Basic Concepts]]

Assembler

2012-12-27T22:08:09Z

Admin:

An assembler is a program that translates assembly language into binary instructions. Assembly language provides a friendlier representation for machine code than a computer’s 0s and 1s bytecode, that simplifies writing and reading programs. Symbolic names (mnemonics) for operations (labels) and locations are one facet of this representation. Another facet is programming facilities that increase a program’s clarity.
 

An assembler (that is a language processor, similar to a compiler) reads a single assembly language source file and produces an object file containing machine instructions in bytecode format and bookkeeping information that helps combine several object files into a program.

[[Category:Basic Concepts]]

Assembler

2012-12-27T22:07:30Z

Admin:

Main Page

2012-12-27T22:05:28Z

Admin: /* Map of Concepts */

Main Page

2012-12-27T22:04:39Z

Admin: /* Map of Concepts */

Main Page

2012-12-27T22:02:58Z

Admin: /* Map of Concepts */

Main Page

2012-12-20T22:08:45Z

Admin:

Abstract Syntax Tree

2012-12-17T11:32:52Z

Admin:

An abstract syntax tree (AST) is a finite, labeled, directed tree, where the internal nodes are labeled by operators, and the leaf nodes represent the operands of the node operators. Thus, the leaves have nullary operators, i.e., variables or constants. In computing, it is used in a parser as an intermediate between a parse tree and a data structure, the latter which is often used as a compiler or interpreter's internal representation of a computer program while it is being optimized and from which code generation is performed. The range of all possible such structures is described by the abstract syntax.
 

An AST differs from a parse tree by omitting nodes and edges for syntax rules that do not affect the semantics of the program. The classic example of such an omission is grouping parentheses, since in an AST the grouping of operands is explicit in the tree structure. Creating an AST in a parser for a language described by a context free grammar, as nearly all programming languages are, is straightforward. Most rules in the grammar create a new node with the nodes edges being the symbols in the rule. Rules that do not contribute to the AST, such as grouping rules, merely pass through the node for one of their symbols. Alternatively, a parser can create a full parse tree, and a post-pass over the parse tree can convert it to an AST by removing the nodes and edges not used in the abstract syntax.

[[Category:Basic Concepts]]

Main Page

2012-12-17T11:18:06Z

Admin: /* Extensões */

It is our purpose to provide theoretical and practical support to those who want to design and process formal (programming or domain specific) languages. So we gathered in this page information about language/grammars and tools (compiler generators), as well as definitions for the basic concepts in compilers area; also information about Virtual Machines (that are becoming now and more important as the compilers target) is available.

== Categories ==
[[Image:b_bc.png|link=Category:Basic Concepts]]
   
[[Image:b_lg.png|link=Category:Languages and Grammars]]
 
[[Image:b_cg.png|link=Category:Compiler Generators]]
   
[[Image:b_vm.png|link=Category:Virtual Machines]]
 
[[Image:b_tu.png|link=Category:Tools & Utilities]]
 

== Map of Concepts ==
[[File:Map.jpg|1000px|link=http://wikipedia.org]]

== Extensões ==
=== MimeTeX ===
<tex>
\operatorname{erfc}(x) =
\frac{2}{\sqrt{\pi}} \int_x^{\infty} e^{-t^2}\,dt =
\frac{e^{-x^2}}{x\sqrt{\pi}}\sum_{n=0}^\infty (-1)^n \frac{(2n)!}{n!(2x)^{2n}}
</tex>

=== SyntaxHighlight ===

<syntaxhighlight lang="php">
<?php
$v = "string"; // sample initialization
?>
html text
<?
echo $v; // end of php code
?>
</syntaxhighlight>

Team

2012-12-16T19:31:43Z

Admin:

* Professor Pedro Manuel Rangel Santos Henriques
** [http://www3.di.uminho.pt/~prh/| Página]

* Professora Daniela Carneiro da Cruz
** [http://alfa.di.uminho.pt/~danieladacruz/| Página]

== Developer ==
* João Miranda, PG22838

MediaWiki:Sidebar

2012-12-16T03:41:57Z

Admin:

MediaWiki:Sidebar

2012-12-16T03:41:17Z

Admin:

Main Page

2012-12-15T20:21:03Z

Admin: /* Map of Concepts */

Main Page

2012-12-15T20:19:58Z

Admin:

It is our purpose to provide theoretical and practical support to those who want to design and process formal (programming or domain specific) languages. So we gathered in this page information about language/grammars and tools (compiler generators), as well as definitions for the basic concepts in compilers area; also information about Virtual Machines (that are becoming now and more important as the compilers target) is available.

== Categories ==
[[Image:b_bc.png|link=Category:Basic Concepts]]
   
[[Image:b_lg.png|link=Category:Languages and Grammars]]
 
[[Image:b_cg.png|link=Category:Compiler Generators]]
   
[[Image:b_vm.png|link=Category:Virtual Machines]]
 
[[Image:b_tu.png|link=Category:Tools & Utilities]]
 

== Map of Concepts ==
[[File:Map.jpg|1000px]]

== Extensões ==
=== MimeTeX ===
<tex>
\operatorname{erfc}(x) =
\frac{2}{\sqrt{\pi}} \int_x^{\infty} e^{-t^2}\,dt =
\frac{e^{-x^2}}{x\sqrt{\pi}}\sum_{n=0}^\infty (-1)^n \frac{(2n)!}{n!(2x)^{2n}}
</tex>

=== SyntaxHighlight ===

<syntaxhighlight lang="php">
<?php
$v = "string"; // sample initialization
?>
html text
<?
echo $v; // end of php code
?>
</syntaxhighlight>

=== InputBox ===
<inputbox>
type=comment
width=20
buttonlabel=Go
searchbuttonlabel=Search
break=no
</inputbox>

Main Page

2012-12-15T20:18:56Z

Admin: /* Map of Concepts */

It is our purpose to provide theoretical and practical support to those who want to design and process formal (programming or domain specific) languages. So we gathered in this page information about language/grammars and tools (compiler generators), as well as definitions for the basic concepts in compilers area; also information about Virtual Machines (that are becoming now and more important as the compilers target) is available.

== Categories ==
[[Image:b_bc.png|link=Category:Basic Concepts]]
   
[[Image:b_lg.png|link=Category:Languages and Grammars]]
 
[[Image:b_cg.png|link=Category:Compiler Generators]]
   
[[Image:b_vm.png|link=Category:Virtual Machines]]
 
[[Image:b_tu.png|link=Category:Tools & Utilities]]
 

== Extensões ==
=== MimeTeX ===
<tex>
\operatorname{erfc}(x) =
\frac{2}{\sqrt{\pi}} \int_x^{\infty} e^{-t^2}\,dt =
\frac{e^{-x^2}}{x\sqrt{\pi}}\sum_{n=0}^\infty (-1)^n \frac{(2n)!}{n!(2x)^{2n}}
</tex>

=== SyntaxHighlight ===

<syntaxhighlight lang="php">
<?php
$v = "string"; // sample initialization
?>
html text
<?
echo $v; // end of php code
?>
</syntaxhighlight>

=== InputBox ===
<inputbox>
type=comment
width=20
buttonlabel=Go
searchbuttonlabel=Search
break=no
</inputbox>

== Map of Concepts ==
[[File:Map.jpg|500px]]

File:Map.jpg

2012-12-15T20:18:13Z

Admin:

Attributes

2012-12-15T19:22:55Z

Admin:

''"Attribute: quality, sign or mark which is charatetristic of something or somebody."'' 
<div align="right">in ''An English-Reader's Dictionary, Oxford University Press''</div>

In general, a set of attributes is used to characterize a family of objects (a class); for a given object (a class instance), each "attribute" has a specific "value" that is said to be an object "property".

In the context of formal language definition, attributes are associated to grammar symbols (non-terminal, or terminal symbols) to specify the language semantics.
For a particular sentence in that language, the values of the set of attributes associated with the grammar axiom (or root symbol) define its specific meaning.
An attribute should be defined for each data item that should be known about each symbol, after the lexical and syntactical analysis of a sentence in order to do the static semantic analysis and its translation or processing.
 

'''See also:''' [http://eplmediawiki.di.uminho.pt/index.php/Inherited_attributes Inherited attributes], [http://eplmediawiki.di.uminho.pt/index.php/Synthesized_Attributes Synthesized attributes]
[[Category:Basic Concepts]]

Attributes

2012-12-15T19:21:56Z

Admin:

''"Attribute: quality, sign or mark which is charatetristic of something or somebody."'' 
<div align="right">in ''An English-Reader's Dictionary, Oxford University Press''</div>

In general, a set of attributes is used to characterize a family of objects (a class); for a given object (a class instance), each "attribute" has a specific "value" that is said to be an object "property".

In the context of formal language definition, attributes are associated to grammar symbols (non-terminal, or terminal symbols) to specify the language semantics.
For a particular sentence in that language, the values of the set of attributes associated with the grammar axiom (or root symbol) define its specific meaning.
An attribute should be defined for each data item that should be known about each symbol, after the lexical and syntactical analysis of a sentence in order to do the static semantic analysis and its translation or processing.
 

'''See also:''' [http://eplmediawiki.di.uminho.pt/index.php/Inherited_attributes Inherited attributes], [http://eplmediawiki.di.uminho.pt/index.php/Synthesized_attributes Synthesized attributes]
[[Category:Basic Concepts]]

Attribute Grammar

2012-12-15T19:21:45Z

Admin:

An attribute grammar is an ordered eighttuple AG = (T, N, S, P, A, R, CC, TR) , where:
- N and T are finite alphabets;
- S is a distinguished symbol of N;
- P is a finite non-empty set pairs (L,R) such that L and R are in (N U T)*;
- A is the union of the inherited and synthesized attributes of a non-terminal X in (N U T)* (if X in N then A(ttributes) (X) = S(inthesized)A(ttributes) U I(nherited)A(ttributes) and the intersection of this two sets is empty; if X in T then A(X) = SA(X) and A(S) = SA(S));
- R = U R(p) is a set of evaluation rules,
- CC = U CC(p) is a set of contextual conditions
- and TR is a set of translation rules.
 

An attribute grammar is a formalism to specify the syntax and semantics of a language; it defines the information that will need to be in the abstract syntax tree to successfully perform semantic analysis and code generation. This information is stored as attributes of the nodes of the abstract syntax tree.
 

The attributes (see also: [http://eplmediawiki.di.uminho.pt/index.php/Attributes Attributes]) are divided into two groups, called synthesized attributes and inherited attributes.
# The '''synthesized attributes''' of a symbol X0, at the root of a tree, store the values that result from attribute evaluation rules using the values of the synthesized attributes of its children nodes (Y1 to Yn) and its own inherited attributes.
# The '''inherited attributes''' of a symbol Yi, i=1..n, at the leaves of a tree, store the values that result from attribute evaluation rules using the values of the synthesized attributes of its sibling nodes and inherited attributes of its parent node (the root of that tree).
 

Basically, synthesized attributes are used to pass semantic information up the parse tree (from leaves to the root), while inherited attributes are used to pass semantic information down the parse tree (propagating values from the root to the leaves). The first is information extracted (directly or after some computation) from the present substring, of the source text, under analysis and processing; the second corresponds to information, available from the context (substrings before or after), that should be taken into consideration for processing the present substring of the source text.

[[Category:Basic Concepts]]

Synthesized Attributes

2012-12-15T19:19:59Z

Admin: Created page with "''Coming soon...'' Category:Basic Concepts"

''Coming soon...''

[[Category:Basic Concepts]]

Category:Basic Concepts

2012-12-11T00:55:03Z

Admin: Protected "Category:Basic Concepts" (‎[edit=sysop] (indefinite) ‎[move=sysop] (indefinite))

Click [{{fullurl:{{FULLPAGENAMEE}}|action=pdfbook}} here] to download this selection of articles as a PDF book.

DynaLab

2012-12-11T00:35:13Z

Admin:

DynaLab (an acronym for DYNAmic LABoratory) provides a dynamic,interactive, hands-on software environment for studying virtually all aspects of programming, as well as time and space complexity issues. The current version of DynaLab supports program animation of Pascal programs, with unbounded reverse execution for repeated study of puzzling program constructs.
Algorithm animation and computer science concept animation are also being incorporated.

== Original Page ==
[http://www.cs.montana.edu/~dynalab/ Link]

== Report ==
A small report relating some details of features of Dynalab ([http://eplmediawiki.di.uminho.pt/uploads/DynaLab.pdf portuguese version]).

 
<div align="right">'''Contribution by:''' [mailto:francisco.oliveira.ext@gmail.com Francisco Oliveira]</div>

[[Category:Tools & Utilities]]
[[Category:Tools]]
[[Category:Pedagogical Tools]]

Gram2C

2012-12-11T00:35:09Z

Admin:

A very useful tool in the context of LP development - [ Gram2C]. missing link
Gram2C works with abstract grammars and syntax trees in C language.

[[Category:Tools & Utilities]]
[[Category:Tools]]
[[Category:Generic Tools]]

File:DynaLab.pdf

2012-12-11T00:34:19Z

Admin:

GraphViz

2012-12-11T00:30:19Z

Admin:

A very useful tool in the context of LP development - [http://www.research.att.com/sw/tools/graphviz/refs.html GraphViz (Reference Manual)].
GraphViz is a system (library and tools) to handle Graphs, namely to plot a graph.

[[Category:Tools & Utilities]]
[[Category:Tools]]
[[Category:Generic Tools]]

VM

2012-12-11T00:27:47Z

Admin:

'''VM''' is a virtual stack-machine that supports integer and float numbers, is slightly different from the usual.
It contains a special stack to save the internal registers to allow the return from functions, and two heaps for dynamic memory allocation---one generic and the other for character strings; it also has graphic primitives.

== Manual (portuguese version) ==
[http://eplmediawiki.di.uminho.pt/uploads/Vmdocpt.pdf Link]

== Original Page ==
[http://www.lri.fr/~paulin/COMPIL/introduction.html Link]

== Examples ==
* [http://eplmediawiki.di.uminho.pt/uploads/Integers.w Integers.w ] 
* [http://eplmediawiki.di.uminho.pt/uploads/Integers.pdf Integers.pdf]

[[Category:Virtual Machines]]

File:Integers.w

2012-12-11T00:24:45Z

Admin:

File:Vmdocpt.pdf

2012-12-11T00:24:45Z

Admin:

File:Integers.pdf

2012-12-11T00:24:43Z

Admin:

Parrot VM

2012-12-11T00:22:39Z

Admin:

'''Parrot''' is a virtual machine designed to efficiently compile and execute bytecode for dynamic languages. Parrot currently hosts a variety of language implementations in various stages of completion, including Tcl, Javascript, Ruby, Lua, Scheme, PHP, Python, Perl 6, APL, and a .NET bytecode translator.
Visit [http://trac.parrot.org/parrot/wiki/Languages this page] for a complete list of languages targeting Parrot.

== Official Site ==
[http://www.parrot.org/ Link]

[[Category:Virtual Machines]]

Yacc

2012-12-11T00:18:55Z

Admin:

''Yacc: Yet Another Compiler-Compiler''

Computer program input generally has some structure; in fact, every computer program that does input can be thought of as defining an "input language" which it accepts.

An input language may be as complex as a programming language, or as simple as a sequence of numbers. Unfortunately, usual input facilities are limited, difficult to use, and often are lax about checking their inputs for validity.

Yacc provides a general tool for describing the input to a computer program. The Yacc user specifies the structures of his input, together with code to be invoked as each such structure is recognized. Yacc turns such a specification into a subroutine that handles the input process; frequently, it is convenient and appropriate to have most of the flow of control in the user's application handled by this subroutine.

== Manual ==
[http://epaperpress.com/lexandyacc/download/yacc.pdf Link]

== Original Page ==
[http://dinosaur.compilertools.net/ Link]

== Examples ==
* [http://eplmediawiki.di.uminho.pt/uploads/Lavanda_LexYacc.w Lavanda.w]
* [http://eplmediawiki.di.uminho.pt/uploads/Lavanda_LexYacc.pdf Lavanda.pdf]

[[Category:Compiler Generators]]

Yacc

2012-12-11T00:18:44Z

Admin:

''Yacc: Yet Another Compiler-Compiler''

Computer program input generally has some structure; in fact, every computer program that does input can be thought of as defining an "input language" which it accepts.

An input language may be as complex as a programming language, or as simple as a sequence of numbers. Unfortunately, usual input facilities are limited, difficult to use, and often are lax about checking their inputs for validity.

Yacc provides a general tool for describing the input to a computer program. The Yacc user specifies the structures of his input, together with code to be invoked as each such structure is recognized. Yacc turns such a specification into a subroutine that handles the input process; frequently, it is convenient and appropriate to have most of the flow of control in the user's application handled by this subroutine.

== Manual ==
[http://epaperpress.com/lexandyacc/download/yacc.pdf Link]

== Original Page ==
[http://dinosaur.compilertools.net/ Link]

== Examples ==
* [http://eplmediawiki.di.uminho.pt/uploads/Lavanda_LexYacc.w Lavanda.w] 
* [http://eplmediawiki.di.uminho.pt/uploads/Lavanda_LexYacc.pdf Lavanda.pdf]

[[Category:Compiler Generators]]