Here is the grammar for our language. Literal values in the grammar are denoted within single quotes. For example, 'LET' indicates that the uppercase characters LET must be observed at that point within the production rule. The grammar is written in a specific form optimal for recursive descent parsing. You can view a graphical form of our grammar on the following website [note, literals must be placed within single quotes within bottlecaps, thus we use the same standard here to make cutting and pasting effective]:

Select which inputs are valid for the statement rule.

 

LET x = 10

 

 

IF x DO print("true"); ELSE print("false");

 

 

IF (x < 10) DO print("true"); END

 

 

FOR EACH IN array DO END

 

 

FOR element IN list DO print(element); END

 

 

WHILE TRUE { print("loop"); }

 

 

RETURN;

 

 

x = 10;

 

 

x.y.z = 10;

 

 

x == 10;

Transcribed Image Text:

source field* method* field::= 'LET' identifier ('=' expression)? ';' method ::= 'DEF' identifier '( (identifier (',' identifier) *)? ')' 'DO' statement* 'END' statement ::= 'LET' identifier ('=' expression)? ';' | 'IF' expression 'DO' statement* ('ELSE' statement*)? 'END' | 'FOR' identifier 'IN' expression 'DO' statement* 'END' | 'WHILE' expression 'DO' statement* 'END' 'RETURN' expression ';' | expression ('=' expression)? ";" expression ::= logical expression logical expression ::= comparison_expression (('AND' | 'OR') comparison_expression)* comparison_expression ::= additive_expression ((' source field* method* field::= 'LET' identifier ('=' expression)? ';' method ::= 'DEF' identifier '( (identifier (',' identifier) *)? ')' 'DO' statement* 'END' statement ::= 'LET' identifier ('=' expression)? ';' | 'IF' expression 'DO' statement* ('ELSE' statement*)? 'END' | 'FOR' identifier 'IN' expression 'DO' statement* 'END' | 'WHILE' expression 'DO' statement* 'END' 'RETURN' expression ';' | expression ('=' expression)? ";" expression ::= logical expression logical expression ::= comparison_expression (('AND' | 'OR') comparison_expression)* comparison_expression ::= additive_expression (('