Rename Crystal::System.print_error(fmt, *args, &) to printf

spec/std/crystal/system_spec.cr

@@ -1,48 +1,48 @@
 require "../spec_helper"
 
-private def print_error_to_s(format, *args)
+private def printf_to_s(format, *args)
   io = IO::Memory.new
-  Crystal::System.print_error(format, *args) do |bytes|
+  Crystal::System.printf(format, *args) do |bytes|
     io.write_string(bytes)
   end
   io.to_s
 end
 
 describe "Crystal::System" do
-  describe ".print_error" do
+  describe ".printf" do
     it "works" do
-      print_error_to_s("abcde").should eq("abcde")
+      printf_to_s("abcde").should eq("abcde")
     end
 
     it "supports %d" do
-      print_error_to_s("%d,%d,%d,%d,%d", 0, 1234, Int32::MAX, Int32::MIN, UInt64::MAX).should eq("0,1234,2147483647,-2147483648,-1")
+      printf_to_s("%d,%d,%d,%d,%d", 0, 1234, Int32::MAX, Int32::MIN, UInt64::MAX).should eq("0,1234,2147483647,-2147483648,-1")
     end
 
     it "supports %u" do
-      print_error_to_s("%u,%u,%u,%u,%u", 0, 1234, UInt32::MAX, Int32::MIN, UInt64::MAX).should eq("0,1234,4294967295,2147483648,4294967295")
+      printf_to_s("%u,%u,%u,%u,%u", 0, 1234, UInt32::MAX, Int32::MIN, UInt64::MAX).should eq("0,1234,4294967295,2147483648,4294967295")
     end
 
     it "supports %x" do
-      print_error_to_s("%x,%x,%x,%x,%x", 0, 0x1234, UInt32::MAX, Int32::MIN, UInt64::MAX).should eq("0,1234,ffffffff,80000000,ffffffff")
+      printf_to_s("%x,%x,%x,%x,%x", 0, 0x1234, UInt32::MAX, Int32::MIN, UInt64::MAX).should eq("0,1234,ffffffff,80000000,ffffffff")
     end
 
     # TODO: investigate why this prints `(???)`
     pending_interpreted "supports %p" do
-      print_error_to_s("%p,%p,%p", Pointer(Void).new(0x0), Pointer(Void).new(0x1234), Pointer(Void).new(UInt64::MAX)).should eq("0x0,0x1234,0xffffffffffffffff")
+      printf_to_s("%p,%p,%p", Pointer(Void).new(0x0), Pointer(Void).new(0x1234), Pointer(Void).new(UInt64::MAX)).should eq("0x0,0x1234,0xffffffffffffffff")
     end
 
     it "supports %s" do
-      print_error_to_s("%s,%s,%s", "abc\0def", "ghi".to_unsafe, Pointer(UInt8).null).should eq("abc\0def,ghi,(null)")
+      printf_to_s("%s,%s,%s", "abc\0def", "ghi".to_unsafe, Pointer(UInt8).null).should eq("abc\0def,ghi,(null)")
     end
 
     # BUG: missing downcast_distinct from Tuple(Int64 | UInt64, Int64 | UInt64, Int64 | UInt64, Int64 | UInt64) to Tuple(Int64, Int64, Int64, Int64)
     pending_interpreted "supports %l width" do
       values = {LibC::Long::MIN, LibC::Long::MAX, LibC::LongLong::MIN, LibC::LongLong::MAX}
-      print_error_to_s("%ld,%ld,%lld,%lld", *values).should eq(values.join(','))
+      printf_to_s("%ld,%ld,%lld,%lld", *values).should eq(values.join(','))
 
       values = {LibC::ULong::MIN, LibC::ULong::MAX, LibC::ULongLong::MIN, LibC::ULongLong::MAX}
-      print_error_to_s("%lu,%lu,%llu,%llu", *values).should eq(values.join(','))
-      print_error_to_s("%lx,%lx,%llx,%llx", *values).should eq(values.join(',', &.to_s(16)))
+      printf_to_s("%lu,%lu,%llu,%llu", *values).should eq(values.join(','))
+      printf_to_s("%lx,%lx,%llx,%llx", *values).should eq(values.join(',', &.to_s(16)))
     end
   end
 end

src/crystal/system/print_error.cr

@@ -3,16 +3,18 @@ module Crystal::System
   # This is useful for error messages from components that are required for
   # IO to work (fibers, scheduler, event_loop).
   def self.print_error(message, *args)
-    print_error(message, *args) do |bytes|
-      {% if flag?(:unix) || flag?(:wasm32) %}
-        LibC.write 2, bytes, bytes.size
-      {% elsif flag?(:win32) %}
-        LibC.WriteFile(LibC.GetStdHandle(LibC::STD_ERROR_HANDLE), bytes, bytes.size, out _, nil)
-      {% end %}
-    end
+    printf(message, *args) { |bytes| print_error(bytes) }
+  end
+
+  def self.print_error(bytes : Bytes) : Nil
+    {% if flag?(:unix) || flag?(:wasm32) %}
+      LibC.write 2, bytes, bytes.size
+    {% elsif flag?(:win32) %}
+      LibC.WriteFile(LibC.GetStdHandle(LibC::STD_ERROR_HANDLE), bytes, bytes.size, out _, nil)
+    {% end %}
   end
 
-  # Minimal drop-in replacement for a C `printf` function. Yields successive
+  # Minimal drop-in replacement for C `printf` function. Yields successive
   # non-empty `Bytes` to the block, which should do the actual printing.
   #
   # *format* only supports the `%(l|ll)?[dpsux]` format specifiers; more should
@@ -23,9 +25,9 @@ module Crystal::System
   # corrupted heap, its implementation should be as low-level as possible,
   # avoiding memory allocations.
   #
-  # NOTE: C's `printf` is incompatible with Crystal's `sprintf`, because the
-  # latter does not support argument width specifiers nor `%p`.
-  def self.print_error(format, *args, &)
+  # NOTE: Crystal's `printf` only supports a subset of C's `printf` format specifiers.
+  # NOTE: MSVC uses `%X` rather than `0x%x`, we follow the latter on all platforms.
+  def self.printf(format, *args, &)
     format = to_string_slice(format)
     format_len = format.size
     ptr = format.to_unsafe
@@ -73,7 +75,6 @@ module Crystal::System
         end
       when 'p'
         read_arg(Pointer(Void)) do |arg|
-          # NOTE: MSVC uses `%X` rather than `0x%x`, we follow the latter on all platforms
           yield "0x".to_slice
           to_int_slice(arg.address, 16, false, 2) { |bytes| yield bytes }
         end