Make semicolons mandatory to eventually allow for expression blocks

This makes the syntax more cluttered, but should eventually be
worth it. Gets rid of automatic semicolon insertion.

README.md

@@ -40,36 +40,36 @@ The following example demonstrates creation of the basic value types.
 Composite types are discussed in [tuple](#tuple), [structure](#structure), etc., below.
 ```
 // initializer is validated against the type annotation
-let b: bool = true
-let i: int = 123
-let f: float = 10.0e-1 
-let s: str = 'abc'
-let f: fn() -> int = || 123
+let b: bool = true;
+let i: int = 123;
+let f: float = 10.0e-1;
+let s: str = 'abc';
+let f: fn() -> int = || 123;
 
 // type is inferred from the initializer
-let b = false
-let i = 40 + 2
-let f = 1.0 * 2
-let s = 'de' + 'f'
-let F = |x| x * 2
+let b = false;
+let i = 40 + 2;
+let f = 1.0 * 2;
+let s = 'de' + 'f';
+let F = |x| x * 2;
 
 // explicit type conversion operator
-let b = 1 as bool
-let i = 2 + 3.4 as int
+let b = 1 as bool;
+let i = 2 + 3.4 as int;
 ```
 
 The previous example showed examples of a simple kind of type inference, where the type of a variable is inferred from an initializer expression (the expression to the right of the `=`).
 Paw supports a more general kind of type inference for containers and closures, where the type of each 'unknown' must be inferred before the declaration in question goes out of scope, or is used in a way in which the type cannot be determined.
 The main caveat here is that Paw does not yet have support for 'generic bounds', so we can't handle, for example, a closure like `|a, b| a + b` where the operator `+` imposes a bound on both `a` and `b`, restricting the types they can be 'instantiated' with (uses the same code as generics).
 For example:
 ```
-let f = |a| a // fn(?0) -> ?0
-f(123) // infer ?0 = int
-f(42)
+let f = |a| a; // fn(?0) -> ?0
+f(123); // infer ?0 = int
+f(42);
 
-let v = [] // [?1]
-v.push('a') // infer ?1 = str
-let s: str = v[0]
+let v = []; // [?1]
+v.push('a'); // infer ?1 = str
+let s: str = v[0];
 ```
 
 ### Variables
@@ -79,10 +79,10 @@ Local variables can be shadowed and 'rebound', and a global item may be shadowed
 Locals can also be captured in the body of a closure (see [closures](#closures)).
 ```
 // initializer (' = 0') is required
-let x: int = 0
+let x: int = 0;
 
 // rebind 'x' to a float (type is inferred from initializer)
-let x = 6.63e-34 
+let x = 6.63e-34;
 ```
 
 ### Scope
@@ -92,7 +92,7 @@ Many language constructs use blocks to create their own scope, like functions, s
 Explicit scoping blocks are also supported.
 ```
 {
-    let x = 42
+    let x = 42;
 } // 'x' goes out of scope here
 ```
 
@@ -104,17 +104,17 @@ Note that named functions can only be defined at the toplevel in Paw.
 ```
 fn fib(n: int) -> int {
     if n < 2 {
-        return n
+        return n;
     }
-    return fib(n - 2) + fib(n - 1)
+    return fib(n - 2) + fib(n - 1);
 }
 ```
 
 ### Closures
 ```
 fn make_fib(n: int) -> fn() -> int {
     // captures 'n'
-    return || fib(n)
+    return || fib(n);
 }
 ```
 
@@ -126,11 +126,11 @@ struct Object {
 }
 
 // all fields must be initialized
-let o = Object{b: 'two', a: 1}
+let o = Object{b: 'two', a: 1};
 
 // unit structs are written without curly braces
-struct Unit
-let u = Unit
+struct Unit;
+let u = Unit;
 ```
 
 ### Enumerations
@@ -141,8 +141,8 @@ enum Choices {
 }
 
 // unit variants are written without parenthesis
-let c = Choices::First
-let c = Choices::Second(123)
+let c = Choices::First;
+let c = Choices::Second(123);
 ```
 
 ### Control flow
@@ -161,44 +161,44 @@ if i == 0 {
 // (must appear in a function that returns Option<T>/Result<T, E>), otherwise, unwraps
 // the Option/Result
 fn maybe() -> Option<int> {
-    let i = maybe_none()?
-    return fallible(i)
+    let i = maybe_none()?;
+    return fallible(i);
 }
 
 // 'break'/'continue' (must appear in a loop):
-break
-continue
+break;
+continue;
 
 // Numeric 'for' loop:
 for i = 0, 10, 2 { // start, end[, step]
     
 }
 
 // 'while' loop:
-let i = 0
+let i = 0;
 while i < 10 {
-    i = i + 1
+    i = i + 1;
 }
 
 // 'do...while' loop:
-let i = 10
+let i = 10;
 do {
-    i = i - 1
-} while i > 0
+    i = i - 1;
+} while i > 0;
 ```
 
 ### Strings
 ```
-let s = 'Hello, world!'
-assert(s.starts_with('Hello'))
-assert(s.ends_with('world!'))
-assert(s[:5].ends_with('Hello'))
-assert(s[-6:].starts_with('world!'))
-assert(1 == s.find('ello'))
-assert(-1 == s.find('Cello'))
+let s = 'Hello, world!';
+assert(s.starts_with('Hello'));
+assert(s.ends_with('world!'));
+assert(s[:5].ends_with('Hello'));
+assert(s[-6:].starts_with('world!'));
+assert(1 == s.find('ello'));
+assert(-1 == s.find('Cello'));
 
-let a = s.split(',')
-assert(s == ','.join(a))
+let a = s.split(',');
+assert(s == ','.join(a));
 ```
 
 ### Generics
@@ -207,16 +207,16 @@ Variables with generic types must be treated generically, that is, they can only
 This allows each template to be type checked a single time, rather than once for each unique instantiation, and makes it easier to generate meaningful error messages.
 ```
 fn map<A, B>(f: fn(A) -> B, vec: [A]) -> [B] {
-    let result = []
+    let result = [];
     for a in vec {
-        result.push(f(a))
+        result.push(f(a));
     }
-    return result
+    return result;
 }
 
 // infer A = float, B = int
-let vec = map(|f: float| f as int, [0.5, 1.5, 2.5])
-assert(vec == [0, 1, 2])
+let vec = map(|f: float| f as int, [0.5, 1.5, 2.5]);
+assert(vec == [0, 1, 2]);
 
 // struct template
 struct Object<S, T> {
@@ -236,67 +236,67 @@ let o = Object{
     b: 'abc', // infer T = str
 }
 // field access using '.'
-let a = o.a + 1
-let b = o.b + 'two'
+let a = o.a + 1;
+let b = o.b + 'two';
 ```
 
 ### Tuples
 ```
-let unit = ()
-let singleton = (42,)
-let pair = (true, 'abc')
-let triplet = (1.0, 'two', 3)
+let unit = ();
+let singleton = (42,);
+let pair = (true, 'abc');
+let triplet = (1.0, 'two', 3);
 
-let a = singleton.0
-let b = pair.1
-let c = triplet.2
+let a = singleton.0;
+let b = pair.1;
+let c = triplet.2;
 ```
 
 ### Vectors
 ```
-let empty: [int] = []
+let empty: [int] = [];
 
 // infer T = str
-let empty = []
-empty.push('a') 
+let empty = [];
+empty.push('a'); 
 
 let vec = [
     [[1, 2, 3], [0]],
     [[4, 5, 6], [1]], 
     [[7, 8, 9], [2]],
 ]
 
-let vec = [1, 2, 3] 
-assert(vec[:1] == [1])
-assert(vec[1:-1] == [2])
-assert(vec[-1:] == [3])
+let vec = [1, 2, 3];
+assert(vec[:1] == [1]);
+assert(vec[1:-1] == [2]);
+assert(vec[-1:] == [3]);
 ```
 
 ### Maps
 ```
-let empty: [int: str] = [:]
+let empty: [int: str] = [:];
 
 // infer K = int, V = str
-let empty = [:]
-empty[0] = 'abc'
+let empty = [:];
+empty[0] = 'abc';
 
-let map = [1: 'a', 2: 'b'] 
-map[3] = 42
-map.erase(1)
+let map = [1: 'a', 2: 'b'];
+map[3] = 42;
+map.erase(1);
 
-assert(m == [2: 'b'])
+assert(m == [2: 'b']);
 
 // prints 'default'
-print(m.get_or(1, 'default'))
+print(m.get_or(1, 'default'));
 ```
 
 ### Error handling
 ```
 fn divide_by_0(n: int) {
-    n = n / 0
+    n = n / 0;
 }
-let status = try(divide_by_0, 42)
-assert(status != 0)
+let status = try(divide_by_0, 42);
+assert(status != 0);
 ```
 
 ## Operators
@@ -324,6 +324,7 @@ assert(status != 0)
 + [x] type inference for `struct` templates and builtin containers
 + [x] sum types/discriminated unions (`enum`)
 + [x] product types (tuple)
++ [ ] Rust-like expression blocks
 + [ ] refactor user-provided allocation interface to allow heap expansion
 + [ ] module system and `import` keyword
 + [ ] methods using `impl` blocks

fuzz/fuzz.c

@@ -4,7 +4,6 @@
 
 #include "fuzz.h"
 #include "lib.h"
-#include "util.h"
 
 extern int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 {

fuzz/seed.paw

@@ -0,0 +1,14 @@
+// seed.paw
+
+fn math_operations() {
+    let a = $
+    let b = $a
+
+    let a = $
+    let b = $
+    let c = a $ b
+}
+
+pub fn main() {
+    math_operations()
+}

src/ast.c

@@ -183,10 +183,8 @@ static void dump_stmt(Printer *P, struct AstStmt *s)
     DUMP_FMT(P, "line: %d\n", s->hdr.line);
     switch (AST_KINDOF(s)) {
         case kAstExprStmt:
-            DUMP_MSG(P, "lhs: ");
-            dump_expr(P, s->expr.lhs);
-            DUMP_MSG(P, "rhs: ");
-            dump_expr(P, s->expr.rhs);
+            DUMP_MSG(P, "expr: ");
+            dump_expr(P, s->expr.expr);
             break;
         case kAstBlock:
             dump_stmt_list(P, s->block.stmts, "stmts");
@@ -308,6 +306,12 @@ static void dump_expr(Printer *P, struct AstExpr *e)
             DUMP_MSG(P, "target: ");
             dump_expr(P, e->unop.target);
             break;
+        case kAstAssignExpr:
+            DUMP_MSG(P, "lhs: ");
+            dump_expr(P, e->assign.lhs);
+            DUMP_MSG(P, "rhs: ");
+            dump_expr(P, e->assign.rhs);
+            break;
         case kAstBinOpExpr:
             DUMP_FMT(P, "op: %d\n", e->binop.op);
             DUMP_MSG(P, "lhs: ");