Objectives:

• To program in python
• To understand the lexical analysis phase of program compilation

Assignment:

The first phase of compilation is called scanning or lexical analysis. This phase interprets the input program as a sequence of characters and produces a sequence of tokens, which will be used by the parser.

Write a Java, C/C++ program that implements a simple scanner for a source file given as a command-line argument. The format of the tokens is described below. You may assume that the input is syntactically correct. Optionally, your program can build a symbol table (a hash table is a good choice), which contains an entry for each token that was found in the input. When all the input has been read, your program should produce a summary report that includes a list of all the tokens that appeared in the input, the number of times each token appears in the input and the class of each token. Your program should also list how many times tokens of each category appeared in the input.

Sample token format:

keyword -> if | then | else | begin | end

identifier -> character | character identifier

integer -> digit | digit integer

real -> integer.integer

special -> ( | ) | [ | ] | + | - | = | , | ;

digit -> 0|1|2|3|4|5|6|7|8|9

character -> a|b|c ... |z|A|B|C ... |Z

More details:

• Case is not used to distinguish tokens.
• The delimiters can be space, tab, newline, and special characters. You only need to use one delimiter in your implementation.
• Choice at least 5 token classes or use the sample ones above.
• Your program output can be ordered in any way you want.