Explain following terms with suitable example.(1) Expansion time variable (3) Semantic expansion (2) Positionalparameter (4) Macro Pre-processo

Expansion Time Variable: In programming, an expansion time variable is a variable that gets its value at the time of expansion. For example, in a makefile, if we have a variable 'x' and we assign it a value 'y' using the '=' operator, then 'x' becomes an expansion time variable. If we change the value of 'y' later in the program, 'x' will still hold the old value of 'y' because 'x' was expanded at the time of assignment.

Positional Parameter: In shell scripting, a positional parameter is a type of variable that holds the command line arguments of a script. For example, if we run a script with the command './myscript arg1 arg2', then 'arg1' and 'arg2' are positional parameters. They can be accessed within the script using the variables '$1', '$2', etc., where the number corresponds to the position of the argument.

Semantic Expansion: Semantic expansion refers to the process of expanding the meaning of a word or phrase based on its context. For example, in natural language processing, if we have the phrase "I am feeling blue", a semantic expansion could interpret "blue" as "sad" based on the context.

Macro Preprocessor: A macro preprocessor is a program that processes macros before compilation. For example, in C programming, the preprocessor handles directives for inclusion of other header files, macro expansions, conditional compilation, and line control. It takes a source code file as input and outputs a modified version of the same file. For instance, if we define a macro '#define PI 3.14', every occurrence of 'PI' in the code will be replaced by '3.14' by the preprocessor before the code is compiled.