Worm PL Interpretter

Jake Armendariz

Wut

Worm is a small interpretted language with heavy static analysis. Its mocked after C and very similar in syntax, with small differences such as a string type and a dynamic list instead of array.

I designed/built Worm this with the goal of building the ideal language to learn. Its C but easy and friendly!

For a great example please check out the worm/arith.c file :)!

Download Requirments

• Rust 2018
• Cargo (rust package manager)

How to Build

• cargo build or make (make puts interpretter binary in directory for easier use)

How to Run

• ./worm-pl worm/
• ./worm-pl worm/tests.c (.c extension for syntax highlighting, this is Worm code, not C)
• ./worm-pl worm/arith.c (works similar to first assignment, user must add input)

Stages

Interpretter currently works in 3 stages

• parsing turns raw text into an AST, catching parser errors
• static analysis type checking, checks all values called exist
• execution runs the abstract syntax tree, code will panic if this fails, as all errors should have been found in previous stages

TODO

• Minimize language (remove list functionality), add a better standard library

Complete

• Strongly typed with checks
• Effective error messages
• Structs
• Types: int, floats, bool, strings, arrays, maps are primary types, each has an array type
• Nested expressions in every case, function calls, indexing
• built in functions, print(), assert()

Effective error messages

• Line and column numbers are provided.
• Uses static analysis, all type, missing type

Error: expected type 'string' recieved type 'char' on 14:16
Error: variable 'd' does not exist on 26:5
Error: function 'providearr' does not exist on 34:15
Error: expected type 'int' recieved type 'string' on 40:9
Error: function 'fuck' does not exist on 45:16
Aborting due to 5 error(s)

Unique

Pass by Value: All parameters are pass by value, not pass by reference.

No Void Function Because all functions are pass by value, every function must have a return value, otherwise they would have no purpose.

Array Definition I tried to create a unique way to declare arrays in worm. Every array can be defined either by a function return or by a [value; size] so if a programmer wants an array of all zeros they can do [0; 20]. For more dynamic changes, I allow a piping of values, so if [|i| i; 20] builds an array counting 0-19. Or even [|index| index^2; 100] builds an array of size 100

map type Integrated into the language is a custom hashmap type that can map from any variable type into any other. Right now there is no type checking involved in this stage, which is clearly a large problem. So to solve this problem, although the map type is from any type to any other, once a key is assigned to a value, the variable type initially assigned to the key is stuck for the lifetime of the hashmap.

Thus, if someone does map["id"] = 0 then map["id"] = "0" there will be a type error, but map["id"] = 2 causes no such violation

Performance

June 3, 2021: Before seperation of execution and function state

35 tests, 0 failures

sudo bash test.sh  3.49s user 0.71s system 89% cpu 4.685 total

After seperation June 3, 2021

35 tests, 0 failures

sudo bash test.sh  1.55s user 0.69s system 86% cpu 2.585 total

March 11, 2022

37 tests, 0 failures

sudo bash test.sh  0.98s user 0.74s system 94% cpu 1.824 total

April 18, 2022: Moved static analysis to references. Only cloning vartypes and strings.

37 tests, 0 failures

sudo bash test.sh  0.98s user 0.74s system 94% cpu 1.824 total