add some docs, allow leading zeros in literals

README.md

@@ -89,16 +89,25 @@ For floating point numbers, only the most basic decimal format is currently impl
 0.464, 3.141, -10.0
 ```
 
-String literals exist in a very basic form. No escape character implemented yet.
+String literals are used for include paths, import names and as literal strings in the data section. The following escapes are supported:
+| Escape | Result | Comment                            |
+| `\"`   | `"`    |                                    |
+| `\'`   | `'`    |                                    |
+| `\t`   | 8      |                                    |
+| `\n`   | 10     |                                    |
+| `\r`   | 13     |                                    |
+| `\N`   | 0x0N   | (Can't be followed by a hex digit) |
+| `\NN`  | 0xNN   |                                    |
 
 ```
 "env.memory", "Hello World!"
 
-this does not work, yet:
-
 "one line\nsecond line", "They said: \"Enough!\""
 ```
 
+Character literals are enclosed in single quotes `'` and support the same escapes as strings. They can contain up to 4 characters and evaluate to the
+little-endian representation of these characters. For examples: `'A'` evaluates to `0x41`, `'hi'` evaluates to 0x6968, and `'Crly'` to 0x7a6c7243.
+
 ### Imports
 
 WebAssembly imports are specified with a module and a name. In CurlyWas you give them inside a single string literal, seperated by a dot. So a module `env` and name `printString` would be written `"env.printString"`.
@@ -295,6 +304,9 @@ So for example this block evaluates to 12:
 
 Blocks are used as function bodies and in flow control (`if`, `block`, `loop`), but can also used at any point inside an expression.
 
+Variable re-assignments of the form `name = name <op> expression` can be shortened to `name <op>= expression`, for example `x += 1` to increment `x` by one. This works for all arithmetic, bit and shift operators.
+The same is allowed for `name := name <op> expression`, ie. `x +:= 1` increments `x` and returns the new value.
+
 #### Flow control
 
 `if condition_expression { if_true_block } [else {if_false_block}]` executes the `if_true_block` if the condition evaluates to a non-zero integer and
@@ -304,6 +316,17 @@ the `if_false_block` otherwise (if it exists). It can also be used as an express
 let a = if 0 { 2 } else { 3 }; // assigns 3 to a
 ```
 
+If the `if_false_block` contains exactly one `if` expression or statement you may omit the curly braces, writing `else if` chains like:
+```
+if x == 0 {
+    doOneThing()
+} else if x == 1 {
+    doThatOtherThing()
+} else {
+    keepWaiting()
+}
+```
+
 `block name { ... }` opens a named block scope. A branch statement can be used to jump to the end of the block. Currently, `block` can only be used
 as a statement, returning a value from the block is not yet supported.
 

src/parser.rs

@@ -250,23 +250,23 @@ fn report_errors(errors: Vec<Simple<String, Span>>, sources: &Sources) {
 
 type LexerError = Simple<char, Span>;
 fn lexer() -> impl Parser<char, Vec<(Token, Span)>, Error = LexerError> {
-    let float64 = text::int(10)
+    let float64 = text::digits(10)
         .chain::<char, _, _>(just('.').chain(text::digits(10)))
         .then_ignore(just("f64"))
         .collect::<String>()
         .map(Token::Float64);
 
-    let float = text::int(10)
+    let float = text::digits(10)
         .chain::<char, _, _>(just('.').chain(text::digits(10)))
         .collect::<String>()
         .map(Token::Float);
 
     let integer = just::<_, _, LexerError>("0x")
-        .ignore_then(text::int(16))
+        .ignore_then(text::digits(16))
         .try_map(|n, span| {
             u64::from_str_radix(&n, 16).map_err(|err| LexerError::custom(span, err.to_string()))
         })
-        .or(text::int(10).try_map(|n: String, span: Span| {
+        .or(text::digits(10).try_map(|n: String, span: Span| {
             n.parse::<u64>()
                 .map_err(|err| LexerError::custom(span, err.to_string()))
         }))