Unicode® control characters
Unicode control characters are tags that help with text flow and direction for languages such as Arabic and Hebrew. To install these languages, use Regional and Language Options in Control Panel.
These descriptions are adapted from The Unicode Consortium. The Unicode Standard, Version 2.0. Reading, Massachusetts: Addison-Wesley Developers Press, February 1997.
Left-to-right mark (LRM)
Acts exactly like left-to-right characters, except that it is not displayed. LRM does not have any other semantic effect.
Right-to-left mark (RLM)
Acts exactly like right-to-left characters, except that it is not displayed. RLM does not have any other semantic effect.
Zero width joiner (ZWJ)
Prevents the joining of consecutive characters on output.
Zero width non-joiner (ZWNJ)
Adds a non-joiner between two characters to prevent them from forming a cursive connection with each other when rendered.
Start of left-to-right embedding (LRE)
Signals that a piece of text is to be treated as embedded left-to-right. For example, an English quotation in the middle of an Arabic sentence could be marked as being embedded left-to-right text. (LRE affects word order, not character order.)
Start of right-to-left embedding (RLE)
Signals that a piece of text is to be treated as embedded right-to-left. For example, a Hebrew phrase in the middle of an English quotation could be marked as being embedded right-to-left. (RLE affects word order, not character order.)
Start of left-to-right override (LRO)
Overrides bidirectional character types when required for special cases, such as for part numbers. LRO forces characters to be treated as strong left-to-right characters.
Start of right-to-left override (RLO)
Overrides bidirectional character types when required for special cases, such as for part numbers. RLO forces characters to be treated as strong right-to-left characters.
Pop directional formatting (PDF)
Terminates the effects of the last explicit code (either embedding or override) and restores the bidirectional state to what it was before the last LRE, RLE, RLO, or LRO control characters.
National digit shapes substitution (NADS)
Uses national digit shapes to display the U+0030-U+0039 (ASCII numerals). The national digit shapes are determined by the current user locale.
Nominal (European) digit shapes (NODS)
Uses the nominal digit shapes for the digits U+0030-U+0039 (ASCII digits). Nominal digit shapes are Western digits.
Activate symmetric swapping (ASS)
Indicates whether the term LEFT or RIGHT in pairs of character names, such as parentheses, should be interpreted as meaning opening or closing, respectively. (The default state is activated.)
Inhibit symmetric swapping (ISS)
Turns off the symmetric swapping of characters such as parenthesis, so that left and right continue to mean left and right facing, as opposed to opening and closing, when symmetric swapping is on.
Activate Arabic form shaping (AAFS)
Controls the shaping behavior of the Arabic compatibility characters. During the presentation process, certain letterforms may be joined together in cursive connection or ligatures. The shaping selector codes indicate that the character shape determination (glyph selection) process used to achieve this presentation effect is to be either activated or inhibited. (The default state is inhibited.)
Inhibit Arabic form shaping (IAFS)
Inhibits the character shaping determination process, so that characters are not shaped based on position.
Record Separator (Block separator) (RS)
Begins a new line after each line separator.
Unit Separator (Segment separator) (US)
Begins a new paragraph after each paragraph separator.