/simple-calculator-compiler

For COMP3235 at HKU.

Primary LanguageC

A Simple Calculator Language (sc) - Compiler

To make

make c5c

To run

  • To compile: ./c5c test/fact.sc > out/fact.as
  • To execute using nas: ./nas/nas out/fact.as

Note that there's an abstraction that compiles and executes together. ./run.sh fact is equivalent to the above three instructions.

You can also run all the test cases in /test with ./run_all.sh.

Design of My Language

  • Global variables will only be referenced inside functions but never redefined.
  • I allow for 1,000 global variables, and 100 local variables for each function call
  • Variable names are case-insensitive. Maximum 12 characters.

A program consists of two parts: function definition and the main section. Main: here is different from C's main--it's just the outmost scope. Function definitions can reference global variables in the main section. An example program is shown below:

// -- Function definitions --
// ...
func addOne(x) {
    result = x + one;
    return result;
}
// ...

// -- Main section --
Main:
one = 1;
puti(addOne(10));

The result would be 11.

Test Cases

General TODO

  • Maybe add end at the end? Nah, I think it's used for functions.
  • Add the constraint that the maximum variable name length is 12 characters
  • Need to distinguish between global and local variables
  • Variable modification after definition
  • Finish remaining non-functional language features (e.g., for, while, if)
  • Deal with variable naming case insensitivity
  • Use func xx() { ... } and xx(); to differentiate function definition and call
  • Is there a need to distinguish between function and variable names? I guess no need, just store them in separate tables
  • Probably use two tables, one for global and one for local?
  • Pre-allocate stack space for global & local variables
  • Label/offset should be defined by the first appearance of function/variable declaration OR reference

General FIXME

  • Execution order is problematic... See 'test/var.sc'
  • The current method doesn't work because updates happen only locally... Probably still need something like a hash table for storing variable info
  • test/gets.sc has a bug: after reading the first char, the second string read is skipped. Probably a problem with NAS not flushing its input buffer? Uh better not fix it yet, just leave it be right now
  • test/while.sc is not working...
  • \\ me, test/abs.sc is also not \\\\ working, what the \\!
  • Double nested for loop is not working correctly

Future Work

  • Avoid the use of main: label and allow function declarations everywhere.