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Difference between revisions of "ETrice/GSoC/2012/GACL"

(Grammar)
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Although syntax for GACL is still being designed but here are few thought regarding syntax .  
 
Although syntax for GACL is still being designed but here are few thought regarding syntax .  
 
==== Empty  ====
 
 
  {}
 
  
 
==== TypeDeclaration  ====
 
==== TypeDeclaration  ====
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   y;
 
   y;
 
   y=2    x=y
 
   y=2    x=y
   x=x+4 y=y+5
+
   x=x+4 y=y+0.5
  
 
===== Action =====
 
===== Action =====
 +
 +
*Declares a variable x of type int , declaration ended with newline .
 +
*Declares a variable y , declaration ended with semicolon .
 +
*Instantiate a variable y with value of 2 (2 as expression) (Value of 2 would be type checked and its type would be assigned to y unless and until there exists another assignment of y with type which can be type casted into type of value) instantiation ended with "\t"
 +
*Instantiate a variable x with value of expression y which is currently 2 .
 +
*Assigns variable x with value of expression x+4 which would be solved and accordingly value of x would be assigned
 +
*Assigns variable y with value of expression x+0.5 which would be solved and accordingly value of y would be assigned (In this case type of y would be changed actually while writing it would be statically analyzed whether we need to type cast y and is it possible to type cast ) .
  
 
===== Grammar =====
 
===== Grammar =====
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===== Syntax =====
 
===== Syntax =====
 +
 +
  x+4
 +
  y==z
  
 
===== Action =====
 
===== Action =====
 +
 +
*First One is an example of arithmetic expression and would have same action as it have for an arithmetic expression .
 +
*Second One is an example of Logical expression and it would have same action as it have for a logical expression .
  
 
===== Grammar =====
 
===== Grammar =====

Revision as of 06:37, 30 May 2012

Generic Action Code Language (GACL)

GACL is the language to describe the Detail Code for execution of ROOM Models in eTrice plugin . GACL aims at dealing with all features commonly available in imperative languages , especially Java , C/C++ . It will act as complement of current version of eTrice which uses code written in target language stored in a string as execution code . GACL would make user able to write execution code independent of target language .

Development Details and Core Information

Features of GACL

  • Variable Declarations ( with optional initializers ) and Function Declaration .
  • Comparison & arithmetic expressions .
  • Basic types , and user defined types .
  • If-else blocks and ladders .
  • For , while , for each , enhanched for each .
  • Support for iterators (that can be used by for each loops ) .
  • Function Calls with arguments & diff types i.e. ref/value/address .
  • type checking and as much as possible implicit type casting .
  • Casts corresponding to static casts in C .

Thoughts on Syntax & Grammar

Although syntax for GACL is still being designed but here are few thought regarding syntax .

TypeDeclaration

Syntax
 type prt type xyz int
 type pqr { int Hello , char ch , prt p , op f1:int() , op f2:char(char,char) }    type pqr' {pqr e1}
 prt {pqr p};
Action
  • Declares a type prt ended with whitespace
  • Creates a type xyz same as int where type declaration ended with newline
  • Creates a type pqr representing a structure rather class with abstracted elements Hello of type int , ch of char , p of type prt and f1 and f2 of type op i.e. Operations . f1 and f2 can take use of their arguments and also other elements of pqr i.e. Hello and ch in this case and ended with a tab .
  • Creates a type pqr' with e1 of pqr abstracted in it ended with newline
  • Creates prt declared already with p of type pqr abstracted in it ended with semicolon
Grammar
 { "type" typename [ existingtype | "{" TypeCode "}" ] [";" | "\n" | "\t" | " "] } | {typename typecode}

VariableDeclaration

Syntax
 int x
 y;
 y=2    x=y
 x=x+4 y=y+0.5
Action
  • Declares a variable x of type int , declaration ended with newline .
  • Declares a variable y , declaration ended with semicolon .
  • Instantiate a variable y with value of 2 (2 as expression) (Value of 2 would be type checked and its type would be assigned to y unless and until there exists another assignment of y with type which can be type casted into type of value) instantiation ended with "\t"
  • Instantiate a variable x with value of expression y which is currently 2 .
  • Assigns variable x with value of expression x+4 which would be solved and accordingly value of x would be assigned
  • Assigns variable y with value of expression x+0.5 which would be solved and accordingly value of y would be assigned (In this case type of y would be changed actually while writing it would be statically analyzed whether we need to type cast y and is it possible to type cast ) .
Grammar
 [ type ] varname [ "=" { varname2 | Expression } ] { ";" | "\n" | "\t" | " "}

Expression

Syntax
 x+4
 y==z
Action
  • First One is an example of arithmetic expression and would have same action as it have for an arithmetic expression .
  • Second One is an example of Logical expression and it would have same action as it have for a logical expression .
Grammar
 { ArithmeticExpression | LogicalExpression }

ArithmeticExpression

Syntax
 { Expression { "+" | "-" | "*" | "/" | "**" | "^" | "%" | "div" } Expression } 
| {Expression { "++" | "--" } } | { { "++" | "--" } Expression }

LogicalExpression

Syntax
Action
Grammar
 { Expression { "<" | "<=" | "==" | ">" | ">=" | "|" | "||" | "&" | "&&" | "^" } Expression }

Statement

Syntax
Action
Grammar
 { TypeDeclaration | VariableDeclaration | Expression }

StatementList

Syntax
Action
Grammar
 { Empty | Statement { { "\n" | "\t" | " "}* } Statementlist }

Program

Syntax
Action
Grammar
 {  Statementlist }


Disambiguation

The syntax used to specify the grammar in brief is

  • Things written in double quotes ("") stand as string written in source .
  • Content inside braces ({}) represents required content .
  • Content inside square brackets ([]) represents optional content .
  • Everything rest is either terminal or non-terminals .
  • Empty and statement list need a more thought to be done . We would surely finally come up with a better solution .

Project Proposal

Click Here to see the project proposal at gsoc's website .

Click Here to see the project proposal in my github repository .

Useful Links