reorganize: consolidate demo directories

- Consolidate _demo, _pydemo, _embdemo into single _demo directory structure
- Organize demos by language: _demo/{go,py,c,embed}/
- Categorize demos based on imports:
- Python library demos (py imports) → _demo/py/
- C/C++ library demos (c/cpp imports) → _demo/c/
- Go-specific demos → _demo/go/
- Embedded demos → _demo/embed/
- Move C-related demos (asm*, cabi*, cgo*, linkname, targetsbuild) from go/ to c/
- Update all path references in README.md and GitHub workflows
- Improve demo organization and navigation as requested in #1256

🤖 Generated with [Claude Code](https://claude.ai/code)

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

_demo/c/cgofull/cgofull.go

@@ -106,8 +106,8 @@ import (
 	"fmt"
 	"unsafe"
 
-	"github.com/goplus/llgo/_demo/cgofull/pymod1"
-	"github.com/goplus/llgo/_demo/cgofull/pymod2"
+	"github.com/goplus/llgo/_demo/c/cgofull/pymod1"
+	"github.com/goplus/llgo/_demo/c/cgofull/pymod2"
 )
 
 //export go_callback_not_use_in_go

_demo/c/cppintf/cppintf.go

@@ -3,7 +3,7 @@ package main
 import (
 	"github.com/goplus/lib/c"
 	"github.com/goplus/lib/c/math"
-	"github.com/goplus/llgo/_demo/cppintf/foo"
+	"github.com/goplus/llgo/_demo/c/cppintf/foo"
 )
 
 type Bar struct {

_demo/c/cppmintf/cpp_multi_intf.go

@@ -5,7 +5,7 @@ import (
 
 	"github.com/goplus/lib/c"
 	"github.com/goplus/lib/c/math"
-	"github.com/goplus/llgo/_demo/cppmintf/foo"
+	"github.com/goplus/llgo/_demo/c/cppmintf/foo"
 )
 
 type Bar struct {

_demo/c/go.mod

@@ -0,0 +1,5 @@
+module github.com/goplus/llgo/_demo/c
+
+go 1.20
+
+require github.com/goplus/lib v0.3.0

_demo/c/go.sum

@@ -0,0 +1,2 @@
+github.com/goplus/lib v0.3.0 h1:y0ZGb5Q/RikW1oMMB4Di7XIZIpuzh/7mlrR8HNbxXCA=
+github.com/goplus/lib v0.3.0/go.mod h1:SgJv3oPqLLHCu0gcL46ejOP3x7/2ry2Jtxu7ta32kp0=

_demo/c/llama2-c/run.go

@@ -36,7 +36,6 @@ loop: // parse command line arguments
 	// build the Tokenizer via the tokenizer .bin file
 	var tokenizer llama2.Tokenizer
 	llama2.BuildTokenizer(&tokenizer, tokenizerPath, transformer.Config.VocabSize)
-
 	// build the Sampler
 	var sampler llama2.Sampler
 	llama2.BuildSampler(&sampler, transformer.Config.VocabSize, temperature, topp, rngSeed)

_demo/embed/go.mod

@@ -0,0 +1,5 @@
+module github.com/goplus/llgo/_demo/embed
+
+go 1.20
+
+require github.com/goplus/lib v0.3.0

_demo/embed/go.sum

@@ -0,0 +1,2 @@
+github.com/goplus/lib v0.3.0 h1:y0ZGb5Q/RikW1oMMB4Di7XIZIpuzh/7mlrR8HNbxXCA=
+github.com/goplus/lib v0.3.0/go.mod h1:SgJv3oPqLLHCu0gcL46ejOP3x7/2ry2Jtxu7ta32kp0=

_demo/embed/hello-esp32/main.go

@@ -0,0 +1,16 @@
+package main
+
+import "github.com/goplus/lib/c"
+
+func myprint(s *c.Char) {
+	for i := 0; i < int(c.Strlen(s)); i++ {
+		WriteByte(byte(c.Index(s, i)))
+	}
+}
+
+func main() {
+	for {
+		myprint(c.Str("hello world"))
+		sleep(1)
+	}
+}

_demo/embed/hello-esp32/uart.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	_ "unsafe"
+
+	"github.com/goplus/lib/c"
+)
+
+//go:linkname WriteByte C.board_uart_write_char
+func WriteByte(b byte)
+
+//go:linkname sleep sleep
+func sleep(c c.Int)

_demo/embed/targetsbuild/build.sh

@@ -111,7 +111,7 @@ if [ $# -eq 1 ]; then
 	done < "$target_file"
 else
 	# Use targets from *.json files
-	for target_file in ../../targets/*.json; do
+	for target_file in ../../../targets/*.json; do
 		# Extract target name from filename (remove path and .json extension)
 		target=$(basename "$target_file" .json)
 		targets_to_build+=("$target")
@@ -127,9 +127,9 @@ for target in "${targets_to_build[@]}"; do
 		continue
 	fi
 
-	output=$(../../llgo.sh build -target $target -o hello.out . 2>&1)
+	output=$(../../../llgo.sh build -target $target -o hello.elf . 2>&1)
 	if [ $? -eq 0 ]; then
-		echo ✅ $target `file hello.out`
+		echo ✅ $target `file hello.elf`
 		successful_targets+=("$target")
 	else
 		# Check if output contains warning messages

_demo/embed/targetsbuild/empty.go

@@ -0,0 +1,6 @@
+package main
+
+import _ "github.com/goplus/llgo/_demo/embed/targetsbuild/C"
+
+func main() {
+}

_demo/embed/write-esp32/main.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	_ "unsafe"
+
+	"github.com/goplus/lib/c"
+)
+
+//go:linkname write C.write
+func write(c.Int, *c.Char, c.SizeT) int
+
+func main() {
+	buf := c.Malloc(6)
+	c.Memset(buf, 0, 6)
+	c.Strncpy((*c.Char)(buf), c.Str("abcde"), 5)
+
+	if c.Strcmp((*c.Char)(buf), c.Str("abcde")) == 0 {
+		write(1, c.Str("pass strcmp"), 11)
+	}
+
+	if byte(c.Index((*c.Char)(buf), 0)) == 'a' {
+		write(1, c.Str("pass index"), 10)
+	}
+
+	c.Memset(buf, c.Int('A'), 5)
+	if c.Strcmp((*c.Char)(buf), c.Str("AAAAA")) == 0 {
+		write(1, c.Str("pass memeset"), 11)
+	}
+
+	write(1, (*c.Char)(buf), 5)
+}

_demo/go/async/main.go

@@ -3,8 +3,8 @@ package main
 import (
 	"time"
 
-	"github.com/goplus/llgo/_demo/async/async"
-	"github.com/goplus/llgo/_demo/async/timeout"
+	"github.com/goplus/llgo/_demo/go/async/async"
+	"github.com/goplus/llgo/_demo/go/async/timeout"
 )
 
 func Sleep(i int, d time.Duration) async.Future[int] {

_demo/go/async/timeout/timeout.go

@@ -3,7 +3,7 @@ package timeout
 import (
 	"time"
 
-	"github.com/goplus/llgo/_demo/async/async"
+	"github.com/goplus/llgo/_demo/go/async/async"
 )
 
 func Timeout(d time.Duration) async.Future[async.Void] {

_demo/go/go.mod

@@ -0,0 +1,3 @@
+module github.com/goplus/llgo/_demo/go
+
+go 1.20

_demo/py/callpy/callpy.go

@@ -0,0 +1,12 @@
+package main
+
+import (
+	"github.com/goplus/lib/py"
+	"github.com/goplus/lib/py/math"
+	"github.com/goplus/lib/py/std"
+)
+
+func main() {
+	x := math.Sqrt(py.Float(2))       // x = sqrt(2)
+	std.Print(py.Str("sqrt(2) ="), x) // print("sqrt(2) =", x)
+}

_demo/py/go.mod

@@ -1,4 +1,4 @@
-module github.com/goplus/llgo/_demo
+module github.com/goplus/llgo/_demo/py
 
 go 1.20
 

_demo/py/matrix/matrix.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"github.com/goplus/lib/py"
+	"github.com/goplus/lib/py/numpy"
+	"github.com/goplus/lib/py/std"
+)
+
+func main() {
+	a := py.List(
+		py.List(1.0, 2.0, 3.0),
+		py.List(4.0, 5.0, 6.0),
+		py.List(7.0, 8.0, 9.0),
+	)
+	b := py.List(
+		py.List(9.0, 8.0, 7.0),
+		py.List(6.0, 5.0, 4.0),
+		py.List(3.0, 2.0, 1.0),
+	)
+	x := numpy.Add(a, b)
+	std.Print(py.Str("a+b ="), x)
+}

_demo/py/max/max.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"github.com/goplus/lib/py"
+	"github.com/goplus/lib/py/std"
+)
+
+func main() {
+	x := std.Max(py.Float(3.0), py.Float(9.0), py.Float(23.0), py.Float(100.0))
+	std.Print(x)
+
+	list := py.List(3.0, 9.0, 23.0, 100.0)
+	y := std.Max(std.Iter(list))
+	std.Print(y)
+}

_demo/py/pi/pi.go

@@ -0,0 +1,10 @@
+package main
+
+import (
+	"github.com/goplus/lib/c"
+	"github.com/goplus/lib/py/math"
+)
+
+func main() {
+	c.Printf(c.Str("pi = %f\n"), math.Pi.Float64())
+}

_demo/py/print/print.go

@@ -0,0 +1,11 @@
+package main
+
+import (
+	"github.com/goplus/lib/py"
+	"github.com/goplus/lib/py/std"
+)
+
+func main() {
+	x := py.Float(3.14)
+	std.Print(x)
+}

_demo/py/statistics/statistics.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"github.com/goplus/lib/c"
+	"github.com/goplus/lib/py"
+	"github.com/goplus/lib/py/statistics"
+)
+
+func main() {
+	list := py.List(1.0, 2.0, 3.0, 4.0, 4.0)
+	mean := statistics.Mean(list)
+	c.Printf(c.Str("mean(1, 2, 3, 4, 4) = %f\n"), mean.Float64())
+}

_demo/py/tensor/tensor.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"github.com/goplus/lib/py"
+	"github.com/goplus/lib/py/std"
+	"github.com/goplus/lib/py/torch"
+)
+
+func main() {
+	data := py.List(
+		py.List(1.0, 2.0),
+		py.List(3.0, 4.0),
+	)
+	x := torch.Tensor(data)
+	std.Print(x)
+}

_demo/targetsbuild/empty.go

@@ -1,6 +0,0 @@
-package main
-
-import _ "github.com/goplus/llgo/_demo/targetsbuild/C"
-
-func main() {
-}