Merge pull request #113 from xushiwei/q

demo: genints

README.md

@@ -9,3 +9,38 @@ llgo - A Go compiler based on LLVM
 [![Language](https://img.shields.io/badge/language-Go+-blue.svg)](https://github.com/goplus/gop)
 
 This is a Go compiler based on LLVM in order to better integrate Go with the C ecosystem. It's a subproject of [the Go+ project](https://github.com/goplus/gop).
+
+## How to install
+
+Follow these steps to generate the `llgo` command (its usage is the same as the `go` command):
+
+### on macOS
+
+```sh
+brew update  # execute if needed
+brew install llvm@17
+go install -v ./...
+```
+
+### on Linux
+
+```sh
+echo 'deb http://apt.llvm.org/focal/ llvm-toolchain-focal-17 main' | sudo tee /etc/apt/sources.list.d/llvm.list
+wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+sudo apt-get update  # execute if needed
+sudo apt-get install --no-install-recommends llvm-17-dev
+go install -v ./...
+```
+
+## Demo
+
+The examples of `llgo` are all in the `_demo` directory (it start with `_` to prevent the `go` command from compiling it):
+
+* _demo/genints: closure usage in llgo
+
+### How to run demos
+
+```sh
+cd <demo-directory>  # eg. cd _demo/genints
+llgo run .
+```

_demo/genints/gen_ints.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"github.com/goplus/llgo/c"
+)
+
+type generator struct {
+	val c.Int
+}
+
+func (g *generator) next() c.Int {
+	g.val++
+	return g.val
+}
+
+func genInts(n int, gen func() c.Int) []c.Int {
+	a := make([]c.Int, n)
+	for i := range a {
+		a[i] = gen()
+	}
+	return a
+}
+
+func main() {
+	// generate 5 random integers
+	for _, v := range genInts(5, c.Rand) {
+		c.Printf(c.Str("%d\n"), v)
+	}
+
+	// generate 5 integers, each is double of the previous one
+	initVal := c.Int(1)
+	ints := genInts(5, func() c.Int {
+		initVal *= 2
+		return initVal
+	})
+	for _, v := range ints {
+		c.Printf(c.Str("%d\n"), v)
+	}
+
+	// generate 5 integers, each is incremented by 1
+	g := &generator{val: 1}
+	for _, v := range genInts(5, g.next) {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}

c/c.go

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package c
+
+import "C"
+import "unsafe"
+
+const (
+	LLGoPackage = "decl"
+)
+
+type (
+	Char    = int8
+	Int     = C.int
+	Pointer = unsafe.Pointer
+	FilePtr = unsafe.Pointer
+)
+
+//go:linkname Stdin __stdinp
+var Stdin FilePtr
+
+//go:linkname Stdout __stdoutp
+var Stdout FilePtr
+
+//go:linkname Stderr __stderrp
+var Stderr FilePtr
+
+//go:linkname Str llgo.cstr
+func Str(string) *Char
+
+//go:linkname Advance llgo.advance
+func Advance(ptr Pointer, offset int) Pointer
+
+//go:linkname Alloca llgo.alloca
+func Alloca(size uintptr) Pointer
+
+//go:linkname AllocaCStr llgo.allocaCStr
+func AllocaCStr(s string) *Char
+
+//go:linkname Unreachable llgo.unreachable
+func Unreachable()
+
+//go:linkname Rand C.rand
+func Rand() Int
+
+//go:linkname Malloc C.malloc
+func Malloc(size uintptr) Pointer
+
+//go:linkname Memcpy C.memcpy
+func Memcpy(dst, src Pointer, n uintptr) Pointer
+
+//go:linkname Memset C.memset
+func Memset(s Pointer, c Int, n uintptr) Pointer
+
+//go:linkname Printf C.printf
+func Printf(format *Char, __llgo_va_list ...any) Int
+
+//go:linkname Fprintf C.fprintf
+func Fprintf(fp FilePtr, format *Char, __llgo_va_list ...any) Int