PCAT Compiler

pcatc is a compiler of the PCAT(Pascal Clone with an ATtitude) programming language for Compilers course.

Currently the project is on stage 2, which uses bison to parse the syntax and print corresponding abstract syntax tree.

Getting started

Put the testcases under tests/, with a suffix of .pcat for each PCAT source file.

make
make test

The program also support read source code from stdin if executed without extra arguments. As we can see, in stage 1, we implement

• the basic function to parse the token
• print every token with its line number and column number
• report the errors appered in test20.pcat with format like what gcc presents.

Stage 2

make test

The AST will be printed to stdout. If syntax error happens, the program will print the verbose error information as well as the error location.

The test19.pcat will fail to 'compile' because missing ';' at the end of WHILE statement.

In stage 2, we implement

• building the abstract syntax tree, and print it out to the screen
• basic syntax error report (with error locations).

What I still want to improve is to provide more language relevant scanner messages. I found a webpage lists some Free Pascal compiling error messages.

Stage 3

make test

will display the test result.

./pcatc [input]

will output the AST to stdout and the LLVM IR code to stderr, we can type

$pcatc $file 2>&1 >&- >/dev/null | lli

to directly execute programs from LLVM bitcode.

Currently, the code can pass test01.pcat and test03.pcat.