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This folder contains examples of "calculator" programs in F# and Java that read an arithmetic expression from the command line and print the result of evaluating such expression.

F#/FsLexYacc

• CalculatorLexer.fsl: The F# lexer for arithmetic expressions
• CalculatorParser.fsp: The F# parser for arithmetic expressions
• CalculatorTypesAST.fs: F# types for AST of arithmetic expressions
• Calculator.fsx: The F# script for the calculator

Java/ANTLR4

• Calculator.g: The ANTLR4 grammar for arithmetic expressions.
• Calculator.java: The Java calculator, which uses the parser generated by ANTLR4.

This is instructions assume that you have followed the guidelines to getting started with F# and FSLexYacc and that you are using a terminal on a folder contaning the F# files mentioned above.

Invoke the lexer generator with

mono FsLexYacc.10.0.0/build/fslex/net46/fslex.exe CalculatorLexer.fsl --unicode

Invoke the parser generator with

mono FsLexYacc.10.0.0/build/fsyacc/net46/fsyacc.exe CalculatorParser.fsp --module CalculatorParser

Invoke the calculator with

fsharpi Calculator.fsx

You should be able to interact with the calculator program as follows:

Enter an arithmetic expression: 1
1.0
Enter an arithmetic expression: 1 + 2
3.0
Enter an arithmetic expression: 1 + 2 * 3
7.0

This is instructions assume that you have followed the guidelines to getting started with Java and ANLTR4 and that you are using a terminal on a folder contaning Calculator.g and Calculator.java.

Generate the visitor-based parser with

antlr4 -visitor -no-listener Calculator.g

Compile the program with

javac *.java

Run the program with

java Calculator

You should be able to interact with the calculator program as follows:

Enter an arithmetic expression: 1
1.0
Enter an arithmetic expression: 1 + 2
3.0
Enter an arithmetic expression: 1 + 2 * 3
7.0