function:

function$\_$header $\{$variable$\}$ body

function$\_$header:

FUNCTION IDENTIFIER $[$parameters$]$ RETURNS type ;

variable:

IDENTIFIER : type IS statement ; $|$

IDENTIFIER : LIST OF type IS list ;

list:

$($ expression $\{,$ expression$\})$

parameters:

parameter $\{,$ parameter$\}$

parameter:

IDENTIFIER : type

type:

INTEGER $|$ REAL $|$ CHARACTER

body:

BEGIN statement END ;

statement:

expression ; $|$

WHEN condition $,$ expression : expression ; $|$

SWITCH expression IS $\{$case$\}$ OTHERS ARROW statement ENDSWITCH ; $|$

IF condition THEN statement $\{$ELSIF condition THEN statement$\}$

ELSE statement ENDIF ; $|$

FOLD direction operator list$\_$choice ENDFOLD ;

case:

CASE INT$\_$LITERAL ARROW statement

direction:

LEFT $|$ RIGHT

operator:

ADDOP $|$ MULOP

list$\_$choice:

list $|$

IDENTIFIER

condition:

expression RELOP expression $|$

condition logical$\_$operator condition $|$

$($ condition $)|$

NOTOP condition

logical$\_$operator:

ANDOP $|$ OROP

expression:

$($ expression $)|$

expression arithmetic$\_$operator expression $|$

NEGOP expression $|$

INT$\_$LITERAL $|$ REAL$\_$LITERAL $|$ CHAR$\_$LITERAL $|$

IDENTIFIER $($ expression $)|$

IDENTIFIER

arithmetic$\_$operator: ADDOP $|$ MULOP $|$ MODOP $|$ EXPOP