feat: add file create, delete, writeBytes and FileFlags class to IO module

Implement File.create() and File.delete() static methods with async libuv operations, add writeBytes() instance method for writing at offsets, introduce FileFlags constants class mirroring POSIX open() flags, refactor File.open() to accept flag parameters via openWithFlags(), and update documentation and module registration accordingly.

test/io/file/create.wren

@@ -0,0 +1,22 @@
+import "io" for File
+
+// Create a new file.
+var file = File.create("file.temp")
+System.print(file.isOpen) // expect: true
+System.print(file.size) // expect: 0
+
+file.writeBytes("stuff")
+file.close()
+
+System.print(File.size("file.temp")) // expect: 5
+
+// Overwrite a file.
+file = File.create("file.temp")
+
+// Truncates.
+System.print(file.size) // expect: 0
+file.close()
+
+File.delete("file.temp")
+
+// TODO: Test it cannot be read from.

test/io/file/create_block.wren

@@ -0,0 +1,25 @@
+import "io" for File
+
+// Create a new file.
+var f
+File.create("file.temp") {|file|
+  f = file
+  System.print(file.isOpen) // expect: true
+  System.print(file.size) // expect: 0
+
+  file.writeBytes("stuff")
+}
+
+// Closed on block exit.
+System.print(f.isOpen) // expect: false
+
+System.print(File.size("file.temp")) // expect: 5
+
+// Overwrite a file.
+File.create("file.temp") {|file|
+  // Truncates.
+  System.print(file.size) // expect: 0
+}
+
+File.delete("file.temp")
+// TODO: Test return value.

test/io/file/delete.wren

@@ -0,0 +1,13 @@
+import "io" for File, Stat
+
+// Create a file.
+var file = File.create("file.temp")
+file.close()
+
+File.delete("file.temp")
+
+// TODO: More graceful API to tell if a file exists.
+var error = Fiber.new {
+  Stat.path("file.temp")
+}.try()
+System.print(error) // expect: no such file or directory

test/io/file/delete_nonexistent.wren

@@ -0,0 +1,3 @@
+import "io" for File
+
+File.delete("nonexistent") // expect runtime error: no such file or directory

test/io/file/delete_open.wren

@@ -0,0 +1,14 @@
+import "io" for File, Stat
+
+// Create a file and don't close it.
+var file = File.create("file.temp")
+
+File.delete("file.temp")
+
+file.close()
+
+// TODO: More graceful API to tell if a file exists.
+var error = Fiber.new {
+  Stat.path("file.temp")
+}.try()
+System.print(error) // expect: no such file or directory

test/io/file/open_block.wren

@@ -14,3 +14,4 @@ System.print(stash.isOpen) // expect: false
 System.print(File.open("test/io/file/open_block.wren") {|file|}) // expect: null
 
 // TODO: Test a fiber aborting inside the block.
+// TODO: Test return value.

test/io/file/write_bytes.wren

@@ -0,0 +1,12 @@
+import "io" for File
+
+File.create("file.temp") {|file|
+  // Appends.
+  file.writeBytes("one")
+  file.writeBytes("two")
+  file.writeBytes("three")
+}
+
+System.print(File.read("file.temp")) // expect: onetwothree
+
+File.delete("file.temp")

test/io/file/write_bytes_after_close.wren

@@ -0,0 +1,10 @@
+import "io" for File
+
+var file = File.create("file.temp")
+file.close()
+
+System.print(Fiber.new {
+  file.writeBytes("one")
+}.try()) // expect: File is not open.
+
+File.delete("file.temp")

test/io/file/write_bytes_from_bytes_not_string.wren

@@ -0,0 +1,9 @@
+import "io" for File
+
+System.print(Fiber.new {
+  File.create("file.temp") {|file|
+    file.writeBytes(123, 0)
+  }
+}.try()) // expect: Bytes must be a string.
+
+File.delete("file.temp")

test/io/file/write_bytes_from_offset.wren

@@ -0,0 +1,11 @@
+import "io" for File
+
+File.create("file.temp") {|file|
+  file.writeBytes("prettyshort", 0)
+  file.writeBytes("agoodbitlonger", 2)
+  file.writeBytes("short", 3)
+}
+
+System.print(File.read("file.temp")) // expect: prashortitlonger
+
+File.delete("file.temp")

test/io/file/write_bytes_from_offset_negative.wren

@@ -0,0 +1,9 @@
+import "io" for File
+
+System.print(Fiber.new {
+  File.create("file.temp") {|file|
+    file.writeBytes("", -1)
+  }
+}.try()) // expect: Offset cannot be negative.
+
+File.delete("file.temp")

test/io/file/write_bytes_from_offset_not_integer.wren

@@ -0,0 +1,9 @@
+import "io" for File
+
+System.print(Fiber.new {
+  File.create("file.temp") {|file|
+    file.writeBytes("", 1.2)
+  }
+}.try()) // expect: Offset must be an integer.
+
+File.delete("file.temp")

test/io/file/write_bytes_from_offset_not_num.wren

@@ -0,0 +1,9 @@
+import "io" for File
+
+System.print(Fiber.new {
+  File.create("file.temp") {|file|
+    file.writeBytes("", "string")
+  }
+}.try()) // expect: Offset must be an integer.
+
+File.delete("file.temp")

test/io/file/write_bytes_not_string.wren

@@ -0,0 +1,9 @@
+import "io" for File
+
+System.print(Fiber.new {
+  File.create("file.temp") {|file|
+    file.writeBytes(123)
+  }
+}.try()) // expect: Bytes must be a string.
+
+File.delete("file.temp")