README.md

String-Operations-Language-Parser

The language supports concatenation (+) and "reverse" operators over strings, function definitions and calls, conditionals (if-else i.e, every "if" must be followed by an "else"), and the following logical expression:

• is-prefix-of (string1 prefix string2): Whether string1 is a prefix of string2. All values in the language are strings.

The precedence of the operator expressions is defined as: precedence(if) < precedence(concat) < precedence(reverse).

The parser translates the input language into Java. It uses JavaCUP for the generation of the parser combined with Jflex generated lexer.

We assume that the program input will always be semantically correct. The input language the function declarations must precede all statements.

Execution

• make compile : Compiles the required files for the parser. (Requires jflex)
• make execute : Executes the main program that waits for input in stdin and uses the parser to return the Java code on stdout.
• make clean : Removes all files generated by make compile.

Input examples

Example 1

name()  {
    "John"
}

surname() {
    "Doe"
}

fullname(first_name, sep, last_name) {
    first_name + sep + last_name
}

name()
surname()
fullname(name(), " ", surname())

Example 2

name() {
    "John"
}

repeat(x) {
    x + x
}

cond_repeat(c, x) {
    if (c prefix "yes")
        if("yes" prefix c)
            repeat(x)
        else
            x
    else
        x
}

cond_repeat("yes", name())
cond_repeat("no", "Jane")

Example 3

findLangType(langName) {
    if ("Java" prefix langName)
        if(langName prefix "Java")
            "Static"
        else
            if(reverse "script" prefix reverse langName)
                "Dynamic"
            else
                "Unknown"
    else
        if (reverse "script" prefix reverse langName)
            "Probably Dynamic"
        else
            "Unknown"
}

findLangType("Java")
findLangType("Javascript")
findLangType("Typescript")