finch.toml, threads and atomics, finch fmt, C++ files, struct #defines, a struct variable given for its ptr

- finch.toml: name, entry, paths, include, links, libdirs, cflags, ldflags, and [target.windows] etc.;
  finch run / build / test with no file use its entry
- import thread: spawn, join, mutex, cpus; atomic_add/sub/load/store/swap/cas built in
- finch fmt [--check]: indentation by { }, trailing spaces, empty lines; also as LSP formatting
- link "x.cpp" (or in finch.toml): built with the C++ compiler, which then links (FINCH_CXX)
- #define RAYWHITE (Color){ 245, 245, 245, 255 } imports as a Color
- push(body) where push takes ptr[Body]: the same as push(addr(body))
- --target android (NDK clang from ANDROID_NDK_HOME, -llog)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016GzNP6r8dg6WDxUVZy8wjL

tests/tool/fmt_in.fch

@@ -0,0 +1,24 @@
+struct P {
+int x   
+	int y
+}
+
+
+
+fn main() {
+  p := P(x: 1,
+         y: 2)
+      msg := """
+          a {
+            b
+          """
+  if p.x > 0 {
+print("{ \(p.x) }") // } not counted
+  } else {
+ print(msg)
+    }
+  s := "a" +
+       "b"
+   print(s)
+}
+

tests/tool/fmt_out.fch

@@ -0,0 +1,21 @@
+struct P {
+    int x
+    int y
+}
+
+fn main() {
+    p := P(x: 1,
+           y: 2)
+    msg := """
+        a {
+          b
+        """
+    if p.x > 0 {
+        print("{ \(p.x) }") // } not counted
+    } else {
+        print(msg)
+    }
+    s := "a" +
+         "b"
+    print(s)
+}

tests/tool/project/expected.out

@@ -0,0 +1 @@
+hello world 42

tests/tool/project/finch.toml

@@ -0,0 +1,14 @@
+# a project: finch run / build / test here need no file and no flags
+name = "mygame"
+entry = "src/main.fch"
+paths = ["src"]
+include = ["native"]
+links = [
+    "native/glue.cpp",     # C++, built with the C++ compiler
+]
+cflags = ["-DGLUE_BASE=40"]
+
+[target.linux]
+links = ["m"]
+[target.windows]
+links = ["ws2_32"]

tests/tool/project/native/glue.cpp

@@ -0,0 +1,9 @@
+// C++ behind a C header: extern "C" gives the function a name C (and Finch) can call
+#include "glue.h"
+#include <numeric>
+#include <vector>
+
+extern "C" int glue_answer(void) {
+    std::vector<int> v = {1, 1};
+    return GLUE_BASE + std::accumulate(v.begin(), v.end(), 0);
+}

tests/tool/project/native/glue.h

@@ -0,0 +1,7 @@
+#ifdef __cplusplus
+extern "C" {
+#endif
+int glue_answer(void);
+#ifdef __cplusplus
+}
+#endif

tests/tool/project/src/game/world.fch

@@ -0,0 +1,3 @@
+fn hello() -> str {
+    return "world"
+}

tests/tool/project/src/main.fch

@@ -0,0 +1,6 @@
+import "glue.h"
+import game/world
+
+fn main() {
+    print("hello \(world.hello()) \(glue_answer())")
+}

tests/tool/test_blocks.fch

@@ -0,0 +1,30 @@
+// finch test: each test "..." block runs on its own; a failed assert or a runtime error fails only that one
+fn add(int a, int b) -> int {
+    return a + b
+}
+
+fn second([]int xs) -> int {
+    return xs[1]
+}
+
+test "add works" {
+    assert(add(2, 3) == 5)
+    assert(add(-1, 1) == 0, "zero")
+}
+
+test "a failing assert" {
+    x := add(1, 2)
+    assert(x == 4, "x is \(x), not 4")
+}
+
+test "a runtime error fails only this test" {
+    print(second([1]))
+}
+
+test "still runs after the others" {
+    assert("\(1.5, 2) and \(add(1, 1))" == "1.50 and 2")
+}
+
+fn main() {
+    print("main is not run by finch test")
+}

tests/tool/test_blocks.out

@@ -0,0 +1,8 @@
+ok   add works
+FAIL a failing assert
+     test_blocks.fch:17: runtime error: assert failed: x is 3, not 4
+FAIL a runtime error fails only this test
+     test_blocks.fch:7: runtime error: index 1 is out of range (the length is 1)
+ok   still runs after the others
+
+2 passed, 2 failed

tests/tool/trace.fch

@@ -0,0 +1,16 @@
+struct Enemy {
+    []int path
+}
+
+fn Enemy.next(int i) -> int {
+    return self.path[i]
+}
+
+fn step(Enemy e) -> int {
+    return e.next(3)
+}
+
+fn main() {
+    e := Enemy(path: [1, 2])
+    print(step(e))
+}

tests/tool/trace.out

@@ -0,0 +1,4 @@
+trace.fch:6: runtime error: index 3 is out of range (the length is 2)
+  in Enemy.next (trace.fch:6)
+  in step (trace.fch:10)
+  in main (trace.fch:15)