Finch 1.0.0

A small, fast programming language on LLVM with C-like syntax.

- Lexer, recursive-descent parser, single-pass type checker + LLVM IR codegen, O2 pipeline
- Types: int/float/bool/char/str, sized i8..u64/f32/f64, pointers ptr[T] with addr()/.value/null
- Functions (fn ... -> T), if/else, while, for..in, break/continue, Go-style operator precedence
- Implicit conversions only when lossless; literals adapt to their target type
- Runtime checks for division by zero, MIN/-1 and null .value
- C interop: import "header.h" via libclang, link "lib" with pkg-config, link-error advice
- Human-readable errors with source excerpts
- Test suite (34 tests), examples, docs for beginners/technicians/engineers in English and Polish

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/fail/bad_link_name.fn

@@ -0,0 +1,3 @@
+// expect: write just the library's name
+link "libm.so"
+fn main() {}

tests/fail/bool_bitand.fn

@@ -0,0 +1,4 @@
+// expect: for true/false use '&&'
+fn main() {
+    print(true & false)
+}

tests/fail/condition_not_bool.fn

@@ -0,0 +1,5 @@
+// expect: a condition must be bool
+fn main() {
+    if 1 {
+    }
+}

tests/fail/div_zero_const.fn

@@ -0,0 +1,4 @@
+// expect: division by zero
+fn main() {
+    print(1 / 0)
+}

tests/fail/div_zero_runtime.fn

@@ -0,0 +1,5 @@
+// expect: 4: runtime error: division by zero
+fn main() {
+    zero := 0
+    print(10 / zero)
+}

tests/fail/float_to_int.fn

@@ -0,0 +1,5 @@
+// expect: cuts off the fraction
+fn main() {
+    float f = 2.5
+    int n = f
+}

tests/fail/forgot_import.fn

@@ -0,0 +1,4 @@
+// expect: import "math.h"
+fn main() {
+    print(sqrt(2))
+}

tests/fail/lib_hint.fn

@@ -0,0 +1,5 @@
+// expect: link "lib_hint"
+import "lib_hint.h"
+fn main() {
+    print(finch_test_missing(1))
+}

tests/fail/lib_hint.h

@@ -0,0 +1 @@
+int finch_test_missing(int x);

tests/fail/literal_too_big.fn

@@ -0,0 +1,4 @@
+// expect: doesn't fit in u8
+fn main() {
+    u8 b = 300
+}

tests/fail/loop_var_readonly.fn

@@ -0,0 +1,6 @@
+// expect: can't be changed
+fn main() {
+    for i in 0..3 {
+        i = 5
+    }
+}

tests/fail/missing_header.fn

@@ -0,0 +1,3 @@
+// expect: can't find the C header
+import "nope_not_here.h"
+fn main() {}

tests/fail/missing_lib.fn

@@ -0,0 +1,3 @@
+// expect: the library 'definitely_not_a_lib' wasn't found
+link "definitely_not_a_lib"
+fn main() {}

tests/fail/missing_return.fn

@@ -0,0 +1,5 @@
+// expect: can reach its end without returning int
+fn f() -> int {
+    print(1)
+}
+fn main() {}

tests/fail/mixed_signs.fn

@@ -0,0 +1,6 @@
+// expect: can't use '+' on i32 and u32
+fn main() {
+    i32 a = 1
+    u32 b = 2
+    print(a + b)
+}

tests/fail/no_main.fn

@@ -0,0 +1,2 @@
+// expect: there is no main function
+fn helper() {}

tests/fail/non_ascii_name.fn

@@ -0,0 +1,4 @@
+// expect: unexpected character 'ż' (names use only
+fn main() {
+    żółw := 1
+}

tests/fail/null_value.fn

@@ -0,0 +1,5 @@
+// expect: 4: runtime error: used .value on a null pointer
+fn main() {
+    ptr[int] p = null
+    print(p.value)
+}

tests/fail/old_function_syntax.fn

@@ -0,0 +1,4 @@
+// expect: functions start with 'fn'
+int add(int a) {
+    return a
+}

tests/fail/redeclare.fn

@@ -0,0 +1,5 @@
+// expect: already exists
+fn main() {
+    x := 1
+    x := 2
+}

tests/fail/two_statements.fn

@@ -0,0 +1,4 @@
+// expect: put each statement on its own line
+fn main() {
+    x := 1 print(x)
+}

tests/fail/type_mismatch.fn

@@ -0,0 +1,4 @@
+// expect: 'x' must be int, but this is str
+fn main() {
+    int x = "hi"
+}

tests/fail/unclosed_brace.fn

@@ -0,0 +1,3 @@
+// expect: never closed
+fn main() {
+    print(1)

tests/fail/undefined_var.fn

@@ -0,0 +1,4 @@
+// expect: there is no variable named 'y'
+fn main() {
+    print(y)
+}

tests/fail/unreachable.fn

@@ -0,0 +1,5 @@
+// expect: this code can never run
+fn main() {
+    return
+    print(1)
+}

tests/fail/untyped_null.fn

@@ -0,0 +1,4 @@
+// expect: null needs a type
+fn main() {
+    p := null
+}

tests/fail/untyped_ptr.fn

@@ -0,0 +1,6 @@
+// expect: this ptr has no type
+import "stdlib.h"
+fn main() {
+    p := malloc(8)
+    print(p.value)
+}