add documentation

Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:22.04
+FROM ubuntu:22.04 as base
 
 ENV TZ=Europe
 ENV DEBIAN_FRONTEND noninteractive
@@ -14,19 +14,26 @@ RUN stack --compiler ghc-9.4.7 setup
 RUN apt-get -y install python3-pip
 RUN pip install pre-commit
 
-# formatter
-RUN stack install ormolu
+FROM base as build
 
 WORKDIR /peter-lang
-
 COPY . /peter-lang
 
-# cancel the build if there are formatting errors
-RUN ormolu --mode check $(find . -name '*.hs')
-
 # build project
 RUN stack build
 
+FROM build as exe
+ENTRYPOINT ["./peter.sh"]
+CMD ["--help"]
+
+FROM build as test
+
+# formatter
+RUN stack install ormolu
+
+# cancel the build if there are formatting errors
+# RUN ormolu --mode check $(find . -name '*.hs')
+
 # run tests
 RUN stack test
 

README.md

@@ -1,27 +1,139 @@
 # peter-lang
 
-Useless and barely functional toy programming language written in Haskell
+Useless and barely functional toy programming language interpreter written in Haskell from scratch (without any research how to actually lay things out)
+
+The missing link between C and Python
+
+<img src="https://m.media-amazon.com/images/M/MV5BMmQwNWY0MzMtZTgyNy00ZTM1LWI0ZDgtY2Q3NGQ4ZjhhN2U2XkEyXkFqcGdeQXVyODQyNDU4OTk@._V1_.jpg" width="720">
+
+## Syntax
+
+C style syntax with Python like runtime interpretation and built in functions.
+
+### Main
+
+Main function `void main() {}` is the entry point.
 
 ```
 void main() {
-  int i = 1;
-  int k = i + 1;
+  print("Hello, World!");
 }
 ```
 
-## Syntax
+Alternately, statements are executed from top to bottom in case no main is found.
+
+```
+print("Hello, World!");
+```
+
+### Primitives
+
+- void
+- bool
+- int
+- float
+- str
+
+### Conversion
+
+- `str(1)` -> `"1"`
+- `int("1")` -> `1`
+- `float("1.3")` -> `1.3`
+
+#### Operations
+
+There is no operator precedence
+
+| Operation | void | bool | int | float | str |
+| :-------: | :--: | :--: | --- | ----- | --- |
+|     +     |  x   |  x   | ✓   | ✓     | ✓   |
+|     -     |  x   |  x   | ✓   | ✓     | x   |
+|    \*     |  x   |  x   | ✓   | ✓     | x   |
+|    \\     |  x   |  x   | ✓   | x     | x   |
+|     %     |  x   |  x   | ✓   | x     | x   |
+|    ==     |  x   |  ✓   | ✓   | ✓     | ✓   |
+|    !=     |  x   |  ✓   | ✓   | ✓     | ✓   |
+|     <     |  x   |  ✓   | ✓   | ✓     | x   |
+|     >     |  x   |  ✓   | ✓   | ✓     | x   |
+|    <=     |  x   |  ✓   | ✓   | ✓     | x   |
+|    >=     |  x   |  ✓   | ✓   | ✓     | x   |
+|    &&     |  x   |  ✓   | ✓   | x     | x   |
+|   \|\|    |  x   |  ✓   | ✓   | x     | x   |
+
+### Flow Control
+
+If:
+
+```
+if 1 < 2 {
+  i = 1;
+} else {
+  i = -1;
+}
+```
 
-C-Style
+while:
 
 ```
+int j = 0;
+while j < 10 {
+  println(str(j));
+  j = j + 1;
+}
+```
+
+### Functions
+
+```
+int f() {
+  return 42;
+}
+
 void main() {
-  print("Hello, World!");
+  int x = f();
+}
+```
+
+### Structs
+
+```
+struct T {
+  int x;
+  int y;
 }
+
+T t;
+t.x = 2;
 ```
 
-## Limitations
+### Built In
+
+- print -> prints
+- println -> prints line
+- input -> reads stdin
+
+## Limitations & Issues
+
+- left side of operation has to be atomic (because of [left recursive grammar](https://en.wikipedia.org/wiki/Left_recursion))
+- no deep copies of structs (yet)
+- many bugs
+- bad error messages from parser
+
+## Installation
 
-- left side of operation has to be atomic
+### Native
+
+Dependencies:
+
+- [stack](https://docs.haskellstack.org/en/stable/)
+- ghc-9.4.7: `stack --compiler ghc-9.4.7 setup`
+
+### Docker
+
+```bash
+docker build --target exe -t peter .
+docker run peter ./examples/print.mmm
+```
 
 ## Usage
 
@@ -42,9 +154,10 @@ stack run -- ./examples/short_hello_world.mmm
 stack run -- -i "print(\"Hello, World\");"
 ```
 
-### Tests
+## Tests
 
-`stack test`
+- `stack test`
+- `cd ./test/E2E/Interpreter/examples/ && ./check_examples.sh`
 
 ## Formatting
 
@@ -56,4 +169,4 @@ ormolu --mode inplace $(find . -name '*.hs')
 
 ## CI
 
-`docker build .`
+`docker build .` + GitHub Actions

examples/primitives.mmm

@@ -0,0 +1,16 @@
+void v = ();
+bool = true;
+int i = 1;
+float f = 2.0;
+str s = "hello";
+
+println(str(i));
+println(str(f));
+
+if 1 > int("0") {
+    println("bigger")
+}
+
+if 1 < int(3.2) {
+    println("smaller")
+}

peter.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+EXE="stack run --"
+
+$EXE "$@"

src/Interpreter/BuiltIn.hs

@@ -95,6 +95,7 @@ toInt =
     valueToInt :: [Value] -> Int
     valueToInt val = case val of
       [IntValue i] -> i
+      [FloatValue f] -> truncate f
       [StringValue s] -> read s
       _ -> error ("No matching type for toInt: " ++ show val)
 

src/Interpreter/Operation.hs

@@ -34,7 +34,9 @@ interpretOperation Gt (FloatValue left) (FloatValue right) = BoolValue $ left >
 interpretOperation Le (FloatValue left) (FloatValue right) = BoolValue $ left <= right
 interpretOperation Ge (FloatValue left) (FloatValue right) = BoolValue $ left >= right
 interpretOperation Eq (FloatValue left) (FloatValue right) = BoolValue $ left == right
+interpretOperation Neq (FloatValue left) (FloatValue right) = BoolValue $ left /= right
 -- String
 interpretOperation Plus (StringValue left) (StringValue right) = StringValue $ left ++ right
+interpretOperation Eq (StringValue left) (StringValue right) = BoolValue $ left == right
 -- Invalid
 interpretOperation operator left right = error $ "Unsupported operation: " ++ show operator ++ " " ++ show left ++ " " ++ show right

test/E2E/Interpreter/examples/check_examples.sh

@@ -33,3 +33,5 @@ for item in "${file_paths[@]}"; do
     IFS=':' read -r file expected_output <<< "$item"
     check_stdout "$file" "$expected_output"
 done
+
+echo "All tests passed"