# Function

function() {}
fn <- function(arg1, arg2, ...) {
  return(arg1)
}
fn = function(arg1, arg2, ...) {
  return(arg1)
}
fn <<- function(arg1, arg2, ...) {
  return(arg1)
}
fn <- function(arg1, arg2 = 123, ...) {
  return(arg1)
}
fn <- function(arg1, arg2 = xyz, ...) {
  return(arg1)
}

==>

Script(FunctionDeclaration(function,ParamList,Block(BlockOpenBrace,BlockCloseBrace)),
  VariableAssignment(Assignable(Identifier),AssignmentOperator,FunctionDeclaration(function,ParamList(Identifier,Identifier,"..."),Block(BlockOpenBrace,ReturnStatement(return,Identifier),BlockCloseBrace))),
  VariableAssignment(Assignable(Identifier),AssignmentOperator,FunctionDeclaration(function,ParamList(Identifier,Identifier,"..."),Block(BlockOpenBrace,ReturnStatement(return,Identifier),BlockCloseBrace))),
  VariableAssignment(Assignable(Identifier),AssignmentOperator,FunctionDeclaration(function,ParamList(Identifier,Identifier,"..."),Block(BlockOpenBrace,ReturnStatement(return,Identifier),BlockCloseBrace))),
  VariableAssignment(Assignable(Identifier),AssignmentOperator,FunctionDeclaration(function,ParamList(Identifier,NamedArg(Identifier),Numeric,"..."),Block(BlockOpenBrace,ReturnStatement(return,Identifier),BlockCloseBrace))),
  VariableAssignment(Assignable(Identifier),AssignmentOperator,FunctionDeclaration(function,ParamList(Identifier,NamedArg(Identifier),Identifier,"..."),Block(BlockOpenBrace,ReturnStatement(return,Identifier),BlockCloseBrace))))

# Function Call

function() {}()
fn()
fn(arg1, arg2, ...)
fn(arg1, arg2 = 123, arg3 = , "arg4" = xyz, ...)
"fn"()
foo <- fn(arg1, ...)

==>

Script(FunctionCall(FunctionDeclaration(function,ParamList,Block(BlockOpenBrace,BlockCloseBrace)), ArgList),
  FunctionCall(Identifier,ArgList),
  FunctionCall(Identifier,ArgList(Identifier,Identifier)),
  FunctionCall(Identifier,ArgList(Identifier,NamedArg(Identifier),Numeric,NamedArg(Identifier),NamedArg(String),Identifier,"...")),
  FunctionCall(String,ArgList),
  VariableAssignment(Assignable(Identifier),AssignmentOperator,FunctionCall(Identifier,ArgList(Identifier,"..."))))

# If Else

if (T) {1} else {2}
if (T) {1}

==>

Script(IfStatement(if,True(T),Block(BlockOpenBrace,Numeric,BlockCloseBrace),else,Block(BlockOpenBrace,Numeric,BlockCloseBrace)),
  IfStatement(if,True(T),Block(BlockOpenBrace,Numeric,BlockCloseBrace)))

# Repeat

repeat {1}
repeat {next}
repeat {next()}
repeat {break}
repeat {break()}

==>

Script(RepeatStatement(repeat,Block(BlockOpenBrace,Numeric,BlockCloseBrace)),
  RepeatStatement(repeat,Block(BlockOpenBrace,NextStatement(next),BlockCloseBrace)),
  RepeatStatement(repeat,Block(BlockOpenBrace,NextStatement(next),BlockCloseBrace)),
  RepeatStatement(repeat,Block(BlockOpenBrace,BreakStatement(break),BlockCloseBrace)),
  RepeatStatement(repeat,Block(BlockOpenBrace,BreakStatement(break),BlockCloseBrace)))

# While

while(T) {1}

==>

Script(WhileStatement(while,True(T),Block(BlockOpenBrace,Numeric,BlockCloseBrace)))

# For

for(x in xs) {1}

==>

Script(ForStatement(for,Identifier,in,Identifier,Block(BlockOpenBrace,Numeric,BlockCloseBrace)))

# Indexing

ls[1]
ls[[1]]

==>

Script(IndexStatement(Identifier,Numeric),
  IndexStatement(Identifier,Numeric))

# Component/Slot Extraction

foo$x
foo@x

==>

Script(BinaryStatement(Identifier,ExtractionOp,Identifier),
  BinaryStatement(Identifier,ExtractionOp,Identifier))

# Namespace operation

foo::x
foo:::x

==>

Script(BinaryStatement(Identifier,NamespaceOp,Identifier),
  BinaryStatement(Identifier,NamespaceOp,Identifier))

# Binary Expression

1^2
1*2
1/2
1%%2
1+2
1-2
1==2
1!=2
1>=2
1<=2
1%in%ls
x%/%y
x%*%y
x%o%y
x%x%y
x|y
x||y
x&y
x&&y

==>

Script(BinaryStatement(Numeric,ArithOp,Numeric),
  BinaryStatement(Numeric,ArithOp,Numeric),
  BinaryStatement(Numeric,ArithOp,Numeric),
  BinaryStatement(Numeric,ArithOp,Numeric),
  BinaryStatement(Numeric,ArithOp,Numeric),
  BinaryStatement(Numeric,ArithOp,Numeric),
  BinaryStatement(Numeric,CompareOp,Numeric),
  BinaryStatement(Numeric,CompareOp,Numeric),
  BinaryStatement(Numeric,CompareOp,Numeric),
  BinaryStatement(Numeric,CompareOp,Numeric),
  BinaryStatement(Numeric,CompareOp,Identifier),
  BinaryStatement(Identifier,MatrixOp,Identifier),
  BinaryStatement(Identifier,MatrixOp,Identifier),
  BinaryStatement(Identifier,MatrixOp,Identifier),
  BinaryStatement(Identifier,MatrixOp,Identifier),
  BinaryStatement(Identifier,LogicOp,Identifier),
  BinaryStatement(Identifier,LogicOp,Identifier),
  BinaryStatement(Identifier,LogicOp,Identifier),
  BinaryStatement(Identifier,LogicOp,Identifier))