integer := ...
string := ...
note := ...
identifier := ...

expr := integer
expr := string
expr := note
expr := identifier
expr := access
expr := assignment
expr := functionCall

# left associative
access := expr '.' expr

# right associative
asterisk := expr '*' stmt

stmt := asterisk
stmt := block
stmt := return
stmt := functionDefinition

# right associative
assignment := identifier '=' expr

list := '(' ')'
list := '(' expr listTail

listTail := expr ', ' listTail
listTail := ')'

percent := integer '%'

return := 'return' expr

block := '{' stmt* '}'

functionCall := identifier list

functionDefinition := 'function' identifier list block