feat: add pexpect and yaml modules with jinja from-import support

Add new pexpect module for process spawning and interaction, including Spawn class with expect, sendline, and timeout handling. Introduce yaml module for YAML parsing with support for nested structures, lists, and data types. Extend jinja template engine with brace tokenization and FromImportNode for macro imports across templates. Register all new foreign functions in modules.c and include generated demo scripts.

test/pexpect/isalive_test.wren

@@ -0,0 +1,15 @@
+// retoor <retoor@molodetz.nl>
+// nontest
+
+import "pexpect" for Spawn
+import "timer" for Timer
+
+System.print("Creating child")
+var child = Spawn.new("echo test")
+System.print("Child created, pid: %(child.pid)")
+System.print("isalive: %(child.isalive)")
+Timer.sleep(500)
+System.print("After sleep, isalive: %(child.isalive)")
+System.print("buffer: [%(child.buffer)]")
+child.close()
+System.print("Done")

test/pexpect/patterns.wren

@@ -0,0 +1,21 @@
+// retoor <retoor@molodetz.nl>
+
+import "pexpect" for Spawn, Pexpect
+
+var child = Spawn.new("echo 'hello world'")
+var result = child.expect(["world", "hello"])
+System.print(result) // expect: 1
+System.print(child.after) // expect: hello
+child.close()
+
+child = Spawn.new("printf 'abc123def'")
+result = child.expectExact(["123"])
+System.print(result) // expect: 0
+System.print(child.before) // expect: abc
+System.print(child.after) // expect: 123
+child.close()
+
+child = Spawn.new("echo 'test multiple patterns'")
+result = child.expect(["foo", "bar", "multiple"])
+System.print(result) // expect: 2
+child.close()

test/pexpect/properties.wren

@@ -0,0 +1,16 @@
+// retoor <retoor@molodetz.nl>
+
+import "pexpect" for Spawn, Pexpect
+
+var child = Spawn.new("echo test")
+System.print(child.pid > 0) // expect: true
+System.print(child.timeout) // expect: 30
+child.timeout = 5
+System.print(child.timeout) // expect: 5
+System.print(child.maxread) // expect: 2000
+System.print(child.searchwindowsize) // expect: 0
+
+child.expect(["test"])
+child.wait()
+System.print(child.exitstatus == 0) // expect: true
+child.close()

test/pexpect/read_test.wren

@@ -0,0 +1,23 @@
+// retoor <retoor@molodetz.nl>
+// nontest
+
+import "pexpect" for Spawn
+import "timer" for Timer
+
+System.print("1. Creating child")
+var child = Spawn.new("echo hello")
+
+System.print("2. Sleeping 200ms")
+Timer.sleep(200)
+
+System.print("3. Buffer: [%(child.buffer)]")
+System.print("4. isalive: %(child.isalive)")
+
+System.print("5. Calling readNonblocking")
+var data = child.readNonblocking(100, 1)
+System.print("6. Data: [%(data)]")
+
+System.print("7. Buffer after read: [%(child.buffer)]")
+System.print("8. Closing")
+child.close()
+System.print("Done")

test/pexpect/run_simple.wren

@@ -0,0 +1,9 @@
+// retoor <retoor@molodetz.nl>
+// nontest
+
+import "pexpect" for Spawn, Pexpect
+
+System.print("Testing Pexpect.run")
+var output = Pexpect.run("echo test")
+System.print("Output: [%(output)]")
+System.print("Done")

test/pexpect/spawn.wren

@@ -0,0 +1,14 @@
+// retoor <retoor@molodetz.nl>
+
+import "pexpect" for Spawn, Pexpect
+
+var child = Spawn.new("echo hello")
+var result = child.expect(["hello"])
+System.print(result) // expect: 0
+
+child = Spawn.new("cat")
+child.sendline("test input")
+var idx = child.expect(["test input"])
+System.print(idx) // expect: 0
+child.sendeof()
+child.close()

test/pexpect/timeout.wren

@@ -0,0 +1,10 @@
+// retoor <retoor@molodetz.nl>
+
+import "pexpect" for Spawn, Pexpect
+
+var child = Spawn.new("sleep 10")
+child.timeout = 0.5
+var result = child.expect(["never_match"])
+System.print(result) // expect: -2
+child.terminate(true)
+child.close()