# class Psych::Emitter

### Public Class Methods

Psych::Emitter.new(io, options = Psych::Emitter::OPTIONS)
Source

    static VALUE initialize(int argc, VALUE *argv, VALUE self)
    {
        yaml_emitter_t * emitter;
        VALUE io, options;
        VALUE line_width;
        VALUE indent;
        VALUE canonical;

        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        if (rb_scan_args(argc, argv, "11", &io, &options) == 2) {
            line_width = rb_funcall(options, id_line_width, 0);
            indent     = rb_funcall(options, id_indentation, 0);
            canonical  = rb_funcall(options, id_canonical, 0);

            yaml_emitter_set_width(emitter, NUM2INT(line_width));
            yaml_emitter_set_indent(emitter, NUM2INT(indent));
            yaml_emitter_set_canonical(emitter, Qtrue == canonical ? 1 : 0);
        }

        rb_ivar_set(self, id_io, io);
        yaml_emitter_set_output(emitter, writer, (void *)self);

        return self;
    }

Create a new `Psych::Emitter` that writes to `io`.

### Public Instance Methods

alias(anchor)
Source

    static VALUE alias(VALUE self, VALUE anchor)
    {
        yaml_emitter_t * emitter;
        yaml_event_t event;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        if(!NIL_P(anchor)) {
            Check_Type(anchor, T_STRING);
            anchor = rb_str_export_to_enc(anchor, rb_utf8_encoding());
        }

        yaml_alias_event_initialize(
                &event,
                (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor))
                );

        emit(emitter, &event);

        return self;
    }

Emit an alias with `anchor`.

See `Psych::Handler#alias`

canonical
Source

    static VALUE canonical(VALUE self)
    {
        yaml_emitter_t * emitter;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        return (emitter->canonical == 0) ? Qfalse : Qtrue;
    }

Get the output style, canonical or not.

canonical = true
Source

    static VALUE set_canonical(VALUE self, VALUE style)
    {
        yaml_emitter_t * emitter;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        yaml_emitter_set_canonical(emitter, Qtrue == style ? 1 : 0);

        return style;
    }

`Set` the output style to canonical, or not.

end_document(implicit)
Source

    static VALUE end_document(VALUE self, VALUE imp)
    {
        yaml_emitter_t * emitter;
        yaml_event_t event;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        yaml_document_end_event_initialize(&event, imp ? 1 : 0);

        emit(emitter, &event);

        return self;
    }

End a document emission with an `implicit` ending.

See `Psych::Handler#end_document`

end_mapping
Source

    static VALUE end_mapping(VALUE self)
    {
        yaml_emitter_t * emitter;
        yaml_event_t event;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        yaml_mapping_end_event_initialize(&event);

        emit(emitter, &event);

        return self;
    }

Emit the end of a mapping.

See `Psych::Handler#end_mapping`

end_sequence
Source

    static VALUE end_sequence(VALUE self)
    {
        yaml_emitter_t * emitter;
        yaml_event_t event;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        yaml_sequence_end_event_initialize(&event);

        emit(emitter, &event);

        return self;
    }

End sequence emission.

See `Psych::Handler#end_sequence`

end_stream
Source

    static VALUE end_stream(VALUE self)
    {
        yaml_emitter_t * emitter;
        yaml_event_t event;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        yaml_stream_end_event_initialize(&event);

        emit(emitter, &event);

        return self;
    }

End a stream emission

See `Psych::Handler#end_stream`

indentation
Source

    static VALUE indentation(VALUE self)
    {
        yaml_emitter_t * emitter;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        return INT2NUM(emitter->best_indent);
    }

Get the indentation level.

indentation = level
Source

    static VALUE set_indentation(VALUE self, VALUE level)
    {
        yaml_emitter_t * emitter;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        yaml_emitter_set_indent(emitter, NUM2INT(level));

        return level;
    }

`Set` the indentation level to `level`. The level must be less than 10 and greater than 1.

line_width
Source

    static VALUE line_width(VALUE self)
    {
        yaml_emitter_t * emitter;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        return INT2NUM(emitter->best_width);
    }

Get the preferred line width.

line_width = width
Source

    static VALUE set_line_width(VALUE self, VALUE width)
    {
        yaml_emitter_t * emitter;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        yaml_emitter_set_width(emitter, NUM2INT(width));

        return width;
    }

`Set` the preferred line with to `width`.

scalar(value, anchor, tag, plain, quoted, style)
Source

    static VALUE scalar(
            VALUE self,
            VALUE value,
            VALUE anchor,
            VALUE tag,
            VALUE plain,
            VALUE quoted,
            VALUE style
            ) {
        yaml_emitter_t * emitter;
        yaml_event_t event;
        rb_encoding *encoding;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        Check_Type(value, T_STRING);

        encoding = rb_utf8_encoding();

        value = rb_str_export_to_enc(value, encoding);

        if(!NIL_P(anchor)) {
            Check_Type(anchor, T_STRING);
            anchor = rb_str_export_to_enc(anchor, encoding);
        }

        if(!NIL_P(tag)) {
            Check_Type(tag, T_STRING);
            tag = rb_str_export_to_enc(tag, encoding);
        }

        const char *value_ptr = StringValuePtr(value);
        yaml_scalar_event_initialize(
                &event,
                (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor)),
                (yaml_char_t *)(NIL_P(tag) ? NULL : StringValueCStr(tag)),
                (yaml_char_t*)value_ptr,
                (int)RSTRING_LEN(value),
                plain ? 1 : 0,
                quoted ? 1 : 0,
                (yaml_scalar_style_t)NUM2INT(style)
                );

        emit(emitter, &event);

        return self;
    }

Emit a scalar with `value`, `anchor`, `tag`, and a `plain` or `quoted` string type with `style`.

See `Psych::Handler#scalar`

start_document(version, tags, implicit)
Source

    static VALUE start_document(VALUE self, VALUE version, VALUE tags, VALUE imp)
    {
        struct start_document_data data = {
            .self = self,
            .version = version,
            .tags = tags,
            .imp = imp,

            .head = NULL,
        };

        return rb_ensure(start_document_try, (VALUE)&data, start_document_ensure, (VALUE)&data);
    }

Start a document emission with `YAML` `version`, `tags`, and an `implicit` start.

See `Psych::Handler#start_document`

start_mapping(anchor, tag, implicit, style)
Source

    static VALUE start_mapping(
            VALUE self,
            VALUE anchor,
            VALUE tag,
            VALUE implicit,
            VALUE style
            ) {
        yaml_emitter_t * emitter;
        yaml_event_t event;
        rb_encoding *encoding;

        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        encoding = rb_utf8_encoding();

        if(!NIL_P(anchor)) {
            Check_Type(anchor, T_STRING);
            anchor = rb_str_export_to_enc(anchor, encoding);
        }

        if(!NIL_P(tag)) {
            Check_Type(tag, T_STRING);
            tag = rb_str_export_to_enc(tag, encoding);
        }

        yaml_mapping_start_event_initialize(
                &event,
                (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor)),
                (yaml_char_t *)(NIL_P(tag) ? NULL : StringValueCStr(tag)),
                implicit ? 1 : 0,
                (yaml_mapping_style_t)NUM2INT(style)
                );

        emit(emitter, &event);

        return self;
    }

Start emitting a `YAML` map with `anchor`, `tag`, an `implicit` start and end, and `style`.

See `Psych::Handler#start_mapping`

start_sequence(anchor, tag, implicit, style)
Source

    static VALUE start_sequence(
            VALUE self,
            VALUE anchor,
            VALUE tag,
            VALUE implicit,
            VALUE style
            ) {
        yaml_emitter_t * emitter;
        yaml_event_t event;

        rb_encoding * encoding = rb_utf8_encoding();

        if(!NIL_P(anchor)) {
            Check_Type(anchor, T_STRING);
            anchor = rb_str_export_to_enc(anchor, encoding);
        }

        if(!NIL_P(tag)) {
            Check_Type(tag, T_STRING);
            tag = rb_str_export_to_enc(tag, encoding);
        }

        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);

        yaml_sequence_start_event_initialize(
                &event,
                (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor)),
                (yaml_char_t *)(NIL_P(tag) ? NULL : StringValueCStr(tag)),
                implicit ? 1 : 0,
                (yaml_sequence_style_t)NUM2INT(style)
                );

        emit(emitter, &event);

        return self;
    }

Start emitting a sequence with `anchor`, a `tag`, `implicit` sequence start and end, along with `style`.

See `Psych::Handler#start_sequence`

start_stream(encoding)
Source

    static VALUE start_stream(VALUE self, VALUE encoding)
    {
        yaml_emitter_t * emitter;
        yaml_event_t event;
        TypedData_Get_Struct(self, yaml_emitter_t, &psych_emitter_type, emitter);
        Check_Type(encoding, T_FIXNUM);

        yaml_stream_start_event_initialize(&event, (yaml_encoding_t)NUM2INT(encoding));

        emit(emitter, &event);

        return self;
    }

Start a stream emission with `encoding`

See `Psych::Handler#start_stream`