Grammar Reference

The grammar that generates \(\mu\mathcal{G}\) expressions is the following:

start ::= c_formula

c_formula ::=  gnn_formula
                | gnn_formula ";" c_formula 
                | gnn_formula ( "||" gnn_formula )  

gnn_formula ::= label                                                                              
                 | "<" label? "|" label                                                                   
                 | "|" label? ">" label                                                                   
                 | label "(" (c_formula ",")* c_formula ")"                                               
                 | "let" (label_decl "=" c_formula ",")* label_decl "=" c_formula "in" c_formula          
                 | "def" label_decl "(" (label_decl ",")* label_decl ")" "{" c_formula "}" "in" c_formula
                 | "if" c_formula "then" c_formula "else" c_formula                                      
                 | "fix" label_decl "=" c_formula "in" c_formula                                          
                 | "repeat" label_decl "=" c_formula "in" c_formula "for" NUMBER                   
                 | "(" c_formula ")"

label ::= /[a-zA-Z_0-9\+\*\^\-\!\%\&\~\/\@]+/ |  FUNC_GEN

FUNC_GEN ::= /[a-zA-Z_0-9\+\*\^\-\!\%\&\~\/\@]+/ "[" /[^\]\[]+/ "]"

label_decl ::= /[a-zA-Z_0-9\+\*\^\-\!\%\&\~\/\@]+/

COMMENT ::= "#" /[^\n]/*

%ignore COMMENT
%import common.WS
%import common.NUMBER
%import common.UCASE_LETTER
%ignore WS

The reserved symbols and words of \(\mu\mathcal{G}\), which therefore cannot be used as function labels or variable names, are:

|| fix let if then else def in repeat for | < > , ( ) ; [ ] # { }

Warning

Variables should not be named with two initial underscores __, e.g. don't name variables such as __X. Such variables names are used internally for operators.