The compiler carries its runtime and std inside itself; host module for the system it runs on

src/embedded.fch (made by tools/pack.fch, checked by tests/run.sh) holds runtime/finch_rt.c and std/; when they aren't
beside the binary they're written to the cache folder once. All the sh/cmd specifics of the driver (quoting, temp dir,
mkdir, rm, mv, null device, path separator, cache dir, binary stdio) moved into host.fch / host_windows.fch.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015f73FesGZGYPkmDvUcj6QX

src/cimport.fch

@@ -8,6 +8,7 @@
 //
 // C structs by value appear in types as the named type `module "C"`.
 import ast
+import host
 import "clang-c/Index.h"
 link "clang"
 
@@ -101,8 +102,11 @@ fn fixed(ast.Type elem, int count) -> ast.Type {
 // Ask the system C compiler where it looks for headers, so we find the same stdio.h it would.
 fn systemIncludeArgs(str cc) -> []str {
     []str dirs
-    tmp := "/tmp/finch_cc_dirs.txt"
-    shell(cc + " -E -v -x c /dev/null 2> '" + tmp + "' > /dev/null")
+    tmp := host.tempDir() + "/finch_cc_dirs_" + str(host.pid()) + ".txt"
+    empty := host.tempDir() + "/finch_empty_" + str(host.pid()) + ".c"
+    write_file(empty, "")
+    host.run(cc + " -E -v -x c " + host.quote(empty) + " 2> " + host.quote(tmp) + " > " + host.nullDevice())
+    host.remove(empty)
     if !file_exists(tmp) {
         return dirs
     }
@@ -126,7 +130,7 @@ fn systemIncludeArgs(str cc) -> []str {
             dirs.push("-isystem" + l)
         }
     }
-    shell("rm -f '" + tmp + "'")
+    host.remove(tmp)
     return dirs
 }
 

src/host.fch

@@ -0,0 +1,77 @@
+// What differs between the systems the compiler itself runs on: how a command line is quoted and run,
+// where temporary files go, making and removing files. This one is for Linux and macOS (name_windows.fch has
+// the Windows one).
+import "stdlib.h"
+import "unistd.h"
+
+fn quote(str a) -> str {
+    return "'" + a.replace("'", "'\\''") + "'"
+}
+
+// run a command line through the shell; its exit code
+fn run(str cmd) -> int {
+    return shell(cmd)
+}
+
+fn nullDevice() -> str {
+    return "/dev/null"
+}
+
+// the folder for temporary files
+fn tempDir() -> str {
+    t := getenv("TMPDIR")
+    if t.len > 0 {
+        if t.ends_with("/") {
+            return t.sub(0, t.len - 1)
+        }
+        return t
+    }
+    return "/tmp"
+}
+
+fn pathSeparator() -> str {
+    return ":"
+}
+
+fn pid() -> int {
+    return int(getpid())
+}
+
+// the folder the compiler was started in
+fn cwd() -> str {
+    return getenv("PWD")
+}
+
+// where files that are made once and kept go
+fn cacheDir() -> str {
+    x := getenv("XDG_CACHE_HOME")
+    if x.len > 0 {
+        return x + "/finch"
+    }
+    h := getenv("HOME")
+    if h.len > 0 {
+        return h + "/.cache/finch"
+    }
+    return tempDir() + "/finch-cache"
+}
+
+// the editor protocol is bytes, not text lines
+fn binaryStdio() {
+}
+
+fn makeDirs(str path) {
+    shell("mkdir -p " + quote(path))
+}
+
+fn remove(str path) {
+    delete_file(path)
+}
+
+fn removeTree(str path) {
+    shell("rm -rf " + quote(path))
+}
+
+// move a file over another
+fn move(str from, str to) {
+    shell("mv " + quote(from) + " " + quote(to))
+}

src/host_windows.fch

@@ -0,0 +1,97 @@
+// What differs between the systems the compiler itself runs on: how a command line is quoted and run,
+// where temporary files go, making and removing files. This one is for Windows (host.fch is for Linux and macOS).
+import "stdlib.h"
+import "stdio.h"
+import "process.h"
+import "direct.h"
+import "io.h"
+
+// a Windows argument: in double quotes, with the quotes inside doubled up the way CreateProcess reads them
+fn quote(str a) -> str {
+    return "\"" + a.replace("\"", "\\\"") + "\""
+}
+
+// Paths use / inside the compiler; cmd.exe wants \
+fn native(str path) -> str {
+    return path.replace("/", "\\")
+}
+
+// run a command line through cmd.exe; its exit code.
+// system() runs `cmd /c <line>`, and cmd drops the first and last quote of a line that starts with one: so the line
+// gets one more pair around it.
+fn run(str cmd) -> int {
+    return shell("\"" + cmd + "\"")
+}
+
+fn nullDevice() -> str {
+    return "NUL"
+}
+
+fn tempDir() -> str {
+    for name in ["TEMP", "TMP"] {
+        t := getenv(name)
+        if t.len > 0 {
+            return t.replace("\\", "/")
+        }
+    }
+    return "."
+}
+
+fn pathSeparator() -> str {
+    return ";"
+}
+
+fn pid() -> int {
+    return int(getpid())
+}
+
+fn cwd() -> str {
+    here := _getcwd(null, 0)           // C allocates the buffer
+    if here.len == 0 {
+        return "."
+    }
+    return here.replace("\\", "/")
+}
+
+fn cacheDir() -> str {
+    x := getenv("LOCALAPPDATA")
+    if x.len > 0 {
+        return x.replace("\\", "/") + "/finch"
+    }
+    return tempDir() + "/finch-cache"
+}
+
+// the editor protocol is bytes, not text lines: no \r\n translation on stdin and stdout
+fn binaryStdio() {
+    _setmode(0, 32768)              // _O_BINARY
+    _setmode(1, 32768)
+}
+
+fn makeDirs(str path) {
+    p := path.replace("\\", "/")
+    at := 0
+    for part in p.split("/") {
+        if at > 0 {
+            at += 1
+        }
+        at += part.len
+        if part.len == 0 || part.ends_with(":") {
+            continue                // "" before a leading / and the drive letter
+        }
+        _mkdir(p.sub(0, at).ptr)    // fails when it is there already, which is fine
+    }
+}
+
+fn remove(str path) {
+    delete_file(path)
+}
+
+fn removeTree(str path) {
+    shell("\"rmdir /s /q " + quote(native(path)) + " 2> NUL\"")
+}
+
+// move a file over another
+fn move(str from, str to) {
+    delete_file(to)
+    rename(from.ptr, to.ptr)
+}

src/linker.fch

@@ -2,8 +2,7 @@
 // and C files the program asks for, and turn the linker's complaints into something a person can act on.
 import platform
 import cimport
-import "stdlib.h"
-import "unistd.h"
+import host
 
 // 32-bit FNV-1a, as hex: names the cached runtime object after what it was built from
 fn fingerprint(str text) -> str {
@@ -20,20 +19,7 @@ fn fingerprint(str text) -> str {
 }
 
 fn quote(str a) -> str {
-    return "'" + a.replace("'", "'\\''") + "'"
-}
-
-// where files that are made once and kept go: ~/.cache/finch
-fn cacheDir() -> str {
-    x := getenv("XDG_CACHE_HOME")
-    if x.len > 0 {
-        return x + "/finch"
-    }
-    h := getenv("HOME")
-    if h.len > 0 {
-        return h + "/.cache/finch"
-    }
-    return "/tmp/finch-cache"
+    return host.quote(a)
 }
 
 // "-lname", or whatever pkg-config says the library needs
@@ -42,11 +28,11 @@ fn libFlags(str name, platform.Target tg) -> str {
         return "-framework " + quote(name.sub(0, name.len - 10))         // macOS: link "Cocoa.framework"
     }
     if !tg.cross {
-        tmp := "/tmp/finch_pkg_flags.txt"
-        code := shell("pkg-config --libs " + quote(name) + " > '" + tmp + "' 2> /dev/null")
+        tmp := host.tempDir() + "/finch_pkg_flags_" + str(host.pid()) + ".txt"
+        code := host.run("pkg-config --libs " + quote(name) + " > " + quote(tmp) + " 2> " + host.nullDevice())
         if code == 0 && file_exists(tmp) {
             flags := (read_file(tmp) or "").trim()
-            shell("rm -f '" + tmp + "'")
+            host.remove(tmp)
             if flags.len > 0 {
                 return flags
             }
@@ -185,25 +171,27 @@ fn linkFailed(str output, cimport.CImports ci, platform.Target tg) -> int {
 // The runtime, compiled once per system and compiler and kept in the cache folder.
 fn runtimeObject(str rt, platform.Target tg, str cc) -> str! {
     source := try read_file(rt)
-    dir := cacheDir()
+    dir := host.cacheDir()
     obj := dir + "/rt-" + fingerprint(source + cc + tg.triple + "2.5") + ".o"
     if file_exists(obj) {
         return obj
     }
-    shell("mkdir -p " + quote(dir))
-    part := obj + ".part" + str(int(getpid()))
+    host.makeDirs(dir)
+    part := obj + ".part" + str(host.pid())
     pic := " -fPIC"
     if tg.windows {
         pic = ""
     }
     log := part + ".log"
-    code := shell(cc + " -O2" + pic + " -c " + quote(rt) + " -o " + quote(part) + " > " + quote(log) + " 2>&1")
+    code := host.run(cc + " -O2" + pic + " -c " + quote(rt) + " -o " + quote(part) + " > " + quote(log) + " 2>&1")
     if code != 0 {
         text := read_file(log) or ""
-        shell("rm -f " + quote(part) + " " + quote(log))
+        host.remove(part)
+        host.remove(log)
         return error(text + "error: couldn't build the Finch runtime with '" + cc + "' (is a C compiler installed?)")
     }
-    shell("rm -f " + quote(log) + " && mv " + quote(part) + " " + quote(obj))
+    host.remove(log)
+    host.move(part, obj)
     return obj
 }
 
@@ -242,12 +230,13 @@ fn build(Build b, platform.Target tg, cimport.CImports ci) -> int {
         target = " --target=" + tg.triple
     }
     log := b.out + ".log"
-    code := shell(clang + target + " " + b.opt + b.extra + " -w -c " + quote(ll) + " -o " + quote(obj) + " > " + quote(log) + " 2>&1")
-    shell("rm -f " + quote(ll))
+    code := host.run(clang + target + " " + b.opt + b.extra + " -w -c " + quote(ll) + " -o " + quote(obj) + " > " + quote(log) + " 2>&1")
+    host.remove(ll)
     if code != 0 {
         print(read_file(log) or "")
         print("error: clang couldn't compile the program's IR")
-        shell("rm -f " + quote(obj) + " " + quote(log))
+        host.remove(obj)
+        host.remove(log)
         return 1
     }
     cmd := cc + " " + quote(obj) + " " + quote(rtobj) + " -o " + quote(b.out)
@@ -270,10 +259,12 @@ fn build(Build b, platform.Target tg, cimport.CImports ci) -> int {
             if tg.windows {
                 pic = ""
             }
-            c := shell(cc + " -O2" + pic + " -c " + quote(l) + " -o " + quote(o) + " > " + quote(log) + " 2>&1")
+            c := host.run(cc + " -O2" + pic + " -c " + quote(l) + " -o " + quote(o) + " > " + quote(log) + " 2>&1")
             if c != 0 {
                 print((read_file(log) or "") + "error: couldn't compile " + l)
-                shell("rm -f " + quote(obj) + " " + quote(log) + " " + quote(o))
+                host.remove(obj)
+                host.remove(log)
+                host.remove(o)
                 return 1
             }
             temps.push(o)
@@ -284,11 +275,12 @@ fn build(Build b, platform.Target tg, cimport.CImports ci) -> int {
             cmd = cmd + " " + libFlags(l, tg)
         }
     }
-    status := shell(cmd + " > " + quote(log) + " 2>&1")
+    status := host.run(cmd + " > " + quote(log) + " 2>&1")
     output := read_file(log) or ""
-    shell("rm -f " + quote(obj) + " " + quote(log))
+    host.remove(obj)
+    host.remove(log)
     for t in temps {
-        shell("rm -f " + quote(t))
+        host.remove(t)
     }
     if status == 127 {
         print("error: no C compiler found to link with ('" + cc + "'; install one, or set FINCH_CC)")

src/lsp.fch

@@ -5,9 +5,9 @@
 // It asks the compiler instead of being one: for every change it runs `finch index` on the text the editor has
 // (see the index records in gen.fch), and answers from what comes back.
 import json
+import host
 import docs
 import "stdio.h"
-import "unistd.h"
 import "stdlib.h"
 
 // ---------- what one run of the compiler told ----------
@@ -325,17 +325,17 @@ fn parseOutput(str output) -> Analysis {
 
 fn Server.analyse(str path) {
     // the editor's text, as files the compiler can read: it asks for the file by its real name
-    shell("mkdir -p '" + self.tmp + "'")
+    host.makeDirs(self.tmp)
     overlays := ""
     n := 0
     for p in self.docs.keys() {
         copy := self.tmp + "/doc" + str(n) + ".fch"
         write_file(copy, self.docs[p])
-        overlays = overlays + " --overlay '" + p + "=" + copy + "'"
+        overlays = overlays + " --overlay " + host.quote(p + "=" + copy)
         n += 1
     }
     out := self.tmp + "/out.txt"
-    shell("'" + self.self + "' index '" + path + "'" + overlays + " > '" + out + "' 2>&1")
+    host.run(host.quote(self.self) + " index " + host.quote(path) + overlays + " > " + host.quote(out) + " 2>&1")
     a := parseOutput(read_file(out) or "")
     if !a.diag.has {
         self.good[path] = a
@@ -863,13 +863,14 @@ fn Server.answer(json.Json msg) {
 
 // finch lsp
 fn run(str self) -> int {
-    s := Server(self: self, tmp: "/tmp/finch_lsp_" + str(int(getpid())))
+    host.binaryStdio()
+    s := Server(self: self, tmp: host.tempDir() + "/finch_lsp_" + str(host.pid()))
     while true {
         msg := readMessage() or {
             break
         }
         s.answer(msg)
     }
-    shell("rm -rf '" + s.tmp + "'")
+    host.removeTree(s.tmp)
     return 0
 }

src/main.fch

@@ -13,6 +13,8 @@ import cimport
 import platform
 import linker
 import lsp
+import host
+import embedded
 import "stdlib.h"
 
 fn dirOf(str path) -> str {
@@ -129,6 +131,23 @@ fn usage() {
     exit(1)
 }
 
+// The runtime and the standard library are carried inside the compiler (embedded.fch). When they aren't found as
+// files next to it, they are written to the cache folder, once, and used from there.
+fn unpack() -> str {
+    names := embedded.names()
+    dir := host.cacheDir() + "/files-" + linker.fingerprint(embedded.texts().join("\n"))
+    if file_exists(dir + "/done") {
+        return dir
+    }
+    texts := embedded.texts()
+    for i in 0..names.len {
+        host.makeDirs(dirOf(dir + "/" + names[i]))
+        write_file(dir + "/" + names[i], texts[i])
+    }
+    write_file(dir + "/done", "")
+    return dir
+}
+
 fn main([]str args) -> int {
     if args.len == 2 && (args[1] == "version" || args[1] == "--version") {
         print("Finch 2.4.0 (the compiler is written in Finch)")
@@ -196,7 +215,7 @@ fn main([]str args) -> int {
     }
     tg := platform.select(targetName)
     if cmd == "run" {
-        out = "/tmp/finch_run_" + stem(file) + tg.exe
+        out = host.tempDir() + "/finch_run_" + str(host.pid()) + "_" + stem(file) + tg.exe
     } else if shared && !outGiven {
         if tg.windows {
             out = out + ".dll"
@@ -221,9 +240,12 @@ fn main([]str args) -> int {
             loader.std = cand
         }
     }
+    if loader.std.len == 0 {
+        loader.std = unpack() + "/std"
+    }
     loader.overlayPaths = overlayPaths
     loader.overlayFiles = overlayFiles
-    for d in getenv("FINCH_PATH").split(":") {
+    for d in getenv("FINCH_PATH").split(host.pathSeparator()) {
         if d.len > 0 {
             loader.paths.push(d)
         }
@@ -262,7 +284,7 @@ fn main([]str args) -> int {
         print(err)
         return 1
     }
-    ir := gen.generate(loader.progs, loader.files, ci, gen.Options(shared: shared, debug: debug, index: cmd == "index", cwd: getenv("PWD"), target: tg))
+    ir := gen.generate(loader.progs, loader.files, ci, gen.Options(shared: shared, debug: debug, index: cmd == "index", cwd: host.cwd(), target: tg))
     if cmd == "ir" || cmd == "index" {
         print(ir)
         return 0
@@ -283,8 +305,7 @@ fn main([]str args) -> int {
         rt = "runtime/finch_rt.c"
     }
     if !file_exists(rt) {
-        print("error: can't find the Finch runtime (runtime/finch_rt.c)")
-        return 1
+        rt = unpack() + "/runtime/finch_rt.c"
     }
     extra := ""
     if shared {
@@ -301,8 +322,8 @@ fn main([]str args) -> int {
         for a in progArgs {
             quoted.push(linker.quote(a))
         }
-        status := shell(tg.runner + linker.quote(out) + " " + quoted.join(" "))
-        shell("rm -f " + linker.quote(out))
+        status := host.run(tg.runner + linker.quote(out) + " " + quoted.join(" "))
+        host.remove(out)
         return status
     }
     return 0

src/platform.fch

@@ -1,6 +1,7 @@
 // The system a program is built for, and what depends on it: the C compiler that links, the file
 // name of the program, how it is run here, and (through the flags) the C calling convention.
 // The same as src/target.cpp.
+import host
 import "stdlib.h"
 
 struct Target {
@@ -22,10 +23,10 @@ fn firstLine(str text) -> str {
 
 // what clang calls the system it runs on, like x86_64-pc-linux-gnu
 fn hostTriple() -> str {
-    tmp := "/tmp/finch_triple.txt"
-    shell("clang -dumpmachine > '" + tmp + "' 2> /dev/null")
+    tmp := host.tempDir() + "/finch_triple_" + str(host.pid()) + ".txt"
+    host.run("clang -dumpmachine > " + host.quote(tmp) + " 2> " + host.nullDevice())
     out := read_file(tmp) or ""
-    shell("rm -f '" + tmp + "'")
+    host.remove(tmp)
     if out.trim().len == 0 {
         return "x86_64-unknown-linux-gnu"
     }
@@ -34,10 +35,10 @@ fn hostTriple() -> str {
 
 // "windows", "linux", "macos", "arm64" (ARM64 Linux), or a full LLVM triple; "" = this system
 fn select(str name) -> Target {
-    host := hostTriple()
+    hostName := hostTriple()
     t := name
     if name.len == 0 {
-        t = host
+        t = hostName
     } else if name == "windows" {
         t = "x86_64-w64-mingw32"
     } else if name == "linux" {
@@ -45,7 +46,7 @@ fn select(str name) -> Target {
     } else if name == "arm64" || name == "aarch64" || name == "linux-arm64" {
         t = "aarch64-unknown-linux-gnu"
     } else if name == "macos" {
-        if host.starts_with("aarch64") || host.starts_with("arm64") {
+        if hostName.starts_with("aarch64") || hostName.starts_with("arm64") {
             t = "arm64-apple-macosx14.0.0"
         } else {
             t = "x86_64-apple-macosx14.0.0"
@@ -56,8 +57,8 @@ fn select(str name) -> Target {
     tg.msvc = t.contains("msvc")
     tg.darwin = t.contains("apple") || t.contains("darwin") || t.contains("macos")
     tg.arm64 = t.starts_with("aarch64") || t.starts_with("arm64")
-    hostArm := host.starts_with("aarch64") || host.starts_with("arm64")
-    hostDarwin := host.contains("apple") || host.contains("darwin")
+    hostArm := hostName.starts_with("aarch64") || hostName.starts_with("arm64")
+    hostDarwin := hostName.contains("apple") || hostName.contains("darwin")
     tg.cross = tg.windows || tg.darwin != hostDarwin || tg.arm64 != hostArm
     tg.exe = ""
     if tg.windows {
@@ -73,6 +74,8 @@ fn select(str name) -> Target {
         tg.cc = "aarch64-linux-gnu-gcc"
     } else if tg.cross {
         tg.cc = "clang --target=" + t
+    } else if host.pathSeparator() == ";" {
+        tg.cc = "clang"             // Windows has no cc
     } else {
         tg.cc = "cc"
     }