Literals
All literals, apart from comments, in a program are of the following sort: keywords; identifiers (names of variables); operators. Literals are separated using delimiters and by using rules which specify the allowed structure of the literal.
Identifiers
Overloading
A language may allow methods/ operators with similar names, but different signature.
Scope
Namespace/ scope of variables and functions is ordinarily defined by the block of code wherein it is defined.
Implicit scope
But, in some cases, a variable may be defined to have ’implict’ scope. Such variables are automatically used by the compiler when necessary - example to bind an argument not explicitly passed to a function, to convert between data-types.
Expression evaluation
Lazy vs eager evaluation
In lazy eval: length([2+1, 3*2, 1/0, 5-4]) returns 4 without even bothering to evaluate the values in the array. This difference in evaluation becomes important when the computations involved are costly: eg: function calls.
Syntactic sugar
Some languages, for the convenience of the programmer, define shorter ways of writing various frequently used expression types.
Macros
Sometimes, a user may add to syntactic sugar by the definition of ’macros’ or expressions which are evaluated before the program is even parsed by the compiler.