quick language overview

README.md

@@ -1,9 +1,18 @@
 # crud-lang
 
-## What is this?
-- an experimental language for CRUD applications (backend only though, I think)
+## Why?
+1. Existing languages are great, but building web services is bolted on, instead of supported out-of-the-box.
+2. Whereas every company needs an API these days. 
+3. I always have trouble mapping urls the code that handles them.
+4. There is no language (AFAIK) that supports layering. (controllers, services, database access, etc). This pattern is ubiquitous (at least where I live). 
+5. ORM's are awful. Mapping from sql rows to objects is a pain. This should be easy.
+6. Json is ubiquitous. Convention over configuration: A controller returns json by default.
+7. Yes, you can automatically serve json from postgres or whatever, but that is not the point. We want to build services.
+   
+## Now what?
+- an experimental language for CRUD applications (web api's)
 - Enterprise as a first-class citizen
-  - built in types for dates and uuid for example
+  - built-in types for dates and uuid for example
   - collection literals
   - ease of use for CRUD operations, like automatic mapping from sql rows to json
 - a simple, yet powerful language
@@ -20,19 +29,21 @@
 - Services can not call other services, because that is the recipe for spaghetti. Refactor your logic, abstract and put lower level code in utilities.
 - Utilities are allowed to call other utilities. OMG, spaghetti after all! TBD
 - Automatic memory management using an arena per call
+- openapi support
 
-- It is an interpreter written in rust. OMG!
-- And it has everything I like in other languages
-    - strictly typed
-    - [] is a list
-    - {} is a map
-    - no objects, no inheritance
-    - structs and duck typing
-    - everything is an expression
-    - nice iterators.
-    - First class functions? Maybe...
-    - automatic mapping from database to object to json
-    - indenting like python
+### An interpreter written in Rust. 
+OMG!
+And it has everything I like in other languages
+  - strictly typed
+  - [] is a list
+  - {} is a map
+  - no objects, no inheritance
+  - structs and duck typing
+  - everything is an expression
+  - nice iterators.
+  - First class functions? Maybe...
+  - automatic mapping from database to object to json
+  - indenting like python
 
 **types**
 
@@ -66,6 +77,7 @@
     * strings
     * bools
     * chars
+    * lists (as literals)
   * type checking and type inference (although it needs more testing)
   * arithmetic expressions
   * function declaration and calling
@@ -74,7 +86,61 @@
   * basic set of operators, including logical and/or and bitwise operations
   
 ## What's next?
-- collection types: list and map
+- collection types: --list-- and map
 - object/struct types
 - control flow
 - tests
+
+## A quick taste
+**variables**
+```
+let a = 42
+```
+* declares a variable of type i64
+
+or explictly as u32
+```
+let a:u32 = 42
+```
+
+* All variables are mutable right now. Have not come to a decision yet about mutable vs immutable variables.
+* You must declare a variable before using it. Block scoping.
+* There is no ```null```. There is ```void``` though.
+* You must initialize a variable when declaring it.
+
+**strings**
+```
+let b:string = "hello "
+```
+Strings support concatening with +
+```
+let c = b + "world"
+```
+
+**lists**
+```
+let list = ["foo", "bar", 1, 1.0]
+```
+No generic types (yet). A list can hold any type.
+* lists support appending with + 
+```
+let list 2 = list + "baz"
+```
+_note to self: implement adding 2 lists_
+
+**functions**
+```
+fn add(a:i64, b:i64) -> i64:
+    a + b
+```
+* Everything is an expression. 
+* The result of the last expression is returned.
+* There are no semicolons. End-of-line chars serve as delimiters.
+* Having multiple expressions on one line is not allowed.
+* indenting determines a block and therefore the scope.
+
+
+**function calling**
+```
+let sum = add(1,2)
+```