Grammar

Grammar rules

Programm -> Decls stmts

Decls -> Decls Decl |e

Decl -> Type id

Type -> Basic

Stmts -> Stmts Stmt |e

Stmt -> Assign

Assign -> Expr

Expr -> Expr + Term

    | Expr - Term

    | Term

Term -> Term * Unary

    | Term / Unary

    | Unary

Unary -> not Unary

     | minus <Unary>

     | Factor

Basic -> long

    | double

Hier wurde die Grammatik von Unten verkürzt, dass wir die arithmitische Operatoren haben bis anfang Mai habe. die Grammatik bedeckt alle Fälle zu arithmitik wie ihr sieht und ist erweitarbar.

Document Status: Draft / Work in Progress

This article is a draft and work in progress. Feel free to comment and discuss on the issue tracker.

Remarks

Several questions have to be addressed:

• What is the definition of "id“, "num", "basic", "real" und "string"?
• What is the semantic of "if (assign)" for "assign" -> "loc = assign"?
• The grammar is ambiguous for "if else" (Dangling Else). How to solve it (prioritoes)?
• What is the difference between "id" and "loc.id" for "loc"?
• What is the semantic for "break" outside of a loop?

(Author: Sven, Translator: Flo)

Grammar rules

The provided grammmar can be found here: https://github.com/swp-uebersetzerbau-ss13/common/blob/master/doc/quellsprache.pdf?raw=true

program -> decls stmts
block -> {decls stmts}
decls -> decls decl | ϵ
decl -> type *id*;
type -> type [*num*] | *basic* | *record* {decls}
stmts -> stmts stmt | ϵ

stmt -> assign;
     | *if*(assign) stmt
     | *if*( assign ) stmt *else* stmt
     | *while*( assign ) stmt
     | *do* stmt *while* ( assign );
     | *break*;
     | *return*;
     | *return* loc;
     | *print* loc;
     | block
loc -> loc [assign] | *id* | loc.*id*

assign -> loc=assign | bool
bool -> bool||join | join
join -> join&&equality | equality
equality -> equality==rel | equality!=rel | rel
rel -> expr<expr | expr<=expr | expr>=expr | expr>expr | expr
expr -> expr+term | expr-term | term
term -> term*unary | term/unary | unary
unary -> !unary | -unary | factor
factor -> (assign) | loc | *num* | *real* | *true* | *false* | *string*

basic -> long | double | string | bool

string -> " (.*) " //?? escaping?

id -> ...

Note: *...* marks terminals

terminal definition

digit -> [0-9]
digits -> digit+
integralDigits -> -? digits
exponent -> ((e | E) integralDigits)
num -> digits 
real -> digits . digits exponent? | digits exponent
basic -> (long | double | string | bool)
alpha -> [a-zA-Z]
alphaNumeric -> [a-zA-Z0-9]
id -> alpha alphaNumeric*

Semantic

Definition of semantic of each term (if necessary)