thai/wtt.h File Reference

---

Detailed Description

WTT I/O implementation.

WTT stands for Wing Tuk Tee (in Thai, Runs everywhere). It was defined by TACTIS (Thai API Consortium/Thai Industrial Standard) in the NECTEC Thai Software Standard Project (1989-1991), and later endorsed by Thai Industrial Standard Institute (TISI) as TIS 1566-2541 in 1998.

WTT classifies Thai chracter(TIS-620) into 17 types below.

 ITYPE  VALUE SHORT_DESCRIPTION
 CTRL    0    control characters
 NON     1    non composible characters
 CONS    2    consonants
 LV      3    leading vowels
 FV1     4    following vowels 1
 FV2     5    following vowels 2
 FV3     6    following vowels 3
 BV1     7    below vowels 1
 BV2     8    below vowels 2
 BD      9    below diacritics
 TONE    10   tonemarks
 AD1     11   above diacritics 1
 AD2     12   above diacritics 2
 AD3     13   above diacritics 3
 AV1     14   above vowels 1
 AV2     15   above vowels 2
 AV3     16   above vowels 3
 

Functions in thctype.h do basic character classifications while wtt.h classifies a chracter in detail. Please refer to the reference.

TACio_op() checks how to compose two given chracters. The possiblities are Composible (CP), Non-display (XC), Accept (AC), Reject (RJ) and Strict Reject (SR). The values of CP, XC, AC, RJ and SR are difined in wtt.h. And their meanings are:

• CP : second character is displayed in the same cell as the first, also implies an acceptance.
• XC : Do nothing.
• AC : Display second character in the next cell.
• RJ : Discard second character.
• SR : Reject second character only in strict mode.

Enumerations
enum	WTTClass {   CTRL = 0, NON = 1, CONS = 2, LV = 3,   FV1 = 4, FV2 = 5, FV3 = 6, BV1 = 7,   BV2 = 8, BD = 9, TONE = 10, AD1 = 11,   AD2 = 12, AD3 = 13, AV1 = 14, AV2 = 15,   AV3 = 16 }
	Classification of characters in TIS620 according to WTT. More...
enum	WTTOp {   CP = 1, XC = 2, AC = 3, RJ = 4,   SR = 5 }
	Composibility checking tables. More...
Functions
WTTClass	TACchtype (thchar_t c)
	WTT character class.
WTTOp	TACio_op (thchar_t c1, thchar_t c2)
	WTT I/O operation.

---

Enumeration Type Documentation

enum WTTClass

Classification of characters in TIS620 according to WTT.

Enumerator:

CTRL	control chars
NON	non composibles
CONS	consonants
LV	leading vowels
FV1	following vowels 1
FV2	following vowels 2
FV3	following vowels 3
BV1	below vowels 1
BV2	below vowels 2
BD	below diacritics
TONE	tonemarks
AD1	above diacritics 1
AD2	above diacritics 2
AD3	above diacritics 3
AV1	above vowels 1
AV2	above vowels 2
AV3	above vowels 3

enum WTTOp

Composibility checking tables.

Enumerator:

CP	COMPOSIBLE - following char is displayed in the same cell as leading char, also implies ACCEPT
XC	Non-display
AC	ACCEPT - display the following char in the next cell
RJ	REJECT - discard that following char, ignore it
SR	STRICT REJECT - REJECT only if in strict mode

---

Function Documentation

WTTClass TACchtype

(

thchar_t

c

)

WTT character class.

Parameters:

c

: the character

Returns:

WTT character class { CTRL, ..., AV3 }

WTTOp TACio_op	(	thchar_t	c1,
		thchar_t	c2
	)

WTT I/O operation.

Parameters:

	c1	: previous character
	c2	: next character

Returns:

WTT I/O operation { CP, XC, AC, RJ, SR }

---