B4X Requires Chilkat v11.1.0+

Unicode Escape and Unescape Text in StringBuilder

Demonstrates options for unicode escaping non-us-ascii chars and emojis. B4X

Dim success As Boolean = False

Dim sbOriginal As ChilkatStringBuilder
sbOriginal.Initialize
success = sbOriginal.LoadFile("qa_data/txt/utf16_emojis_accented_jap.txt", "utf-16")
If success = False Then
    Log(sbOriginal.LastErrorText)
    Return
End If


'  The above file contains the following text, which includes some emoji's,
'  Japanese chars, and accented chars.

Dim sb As ChilkatStringBuilder
sb.Initialize
sb.AppendSb(sbOriginal)

'  Charset is not used for unicode escaping.  Set it to "utf-8", but it means nothing.
Dim charsetNotUsed As String = "utf-8"

'  Indicate the desired format/style of Unicode escaping.
'  Choose JSON-style (JavaScript-style) Unicode escape sequences by using "unicodeescape"
Dim encoding As String = "unicodeescape"

sb.Encode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  Output:
'  \ud83e\udde0
'  \ud83d\udd10
'  \u2705
'  \u26a0\ufe0f
'  \u274c
'  \u2713
'  \u4e2d
'  \u00e9 xyz \u00e0
'  abc \u79c1 \u306f \u3093 ghi

'  Revert back to the unescaped chars:
sb.Decode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  -----------------------------------------------------------------------------------------
'  Do the same, but use uppercase letters (A-F) in the hex values.
encoding = "unicodeescape-upper"
sb.Encode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  Output:
'  \uD83E\uDDE0
'  \uD83D\uDD10
'  \u2705
'  \u26A0\uFE0F
'  \u274C
'  \u2713
'  \u4E2D
'  \u00E9 xyz \u00E0
'  abc \u79C1 \u306F \u3093 ghi

'  Revert back to the unescaped chars:
sb.Decode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  -----------------------------------------------------------------------------------------
'   ECMAScript (JavaScript) �code point escape� syntax

encoding = "unicodeescape-curly"
sb.Encode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  Output:
'  \u{d83e}\u{dde0}
'  \u{d83d}\u{dd10}
'  \u{2705}
'  \u{26a0}\u{fe0f}
'  \u{274c}
'  \u{2713}
'  \u{4e2d}
'  \u{00e9} xyz \u{00e0}
'  abc \u{79c1} \u{306f} \u{3093} ghi

'  Revert back to the unescaped chars:
sb.Decode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  -----------------------------------------------------------------------------------------
'  Do the same, but use uppercase letters (A-F) in the hex values.
encoding = "unicodeescape-curly-upper"
sb.Encode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  Output:
'  \u{D83E}\u{DDE0}
'  \u{D83D}\u{DD10}
'  \u{2705}
'  \u{26A0}\u{FE0F}
'  \u{274C}
'  \u{2713}
'  \u{4E2D}
'  \u{00E9} xyz \u{00E0}
'  abc \u{79C1} \u{306F} \u{3093} ghi

'  Revert back to the unescaped chars:
sb.Decode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  -----------------------------------------------------------------------------------------
'  HTML hexadecimal character reference

encoding = "unicodeescape-htmlhex"
sb.Encode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  Output:
'  🧠
'  🔐
'  ✅
'  ⚠️
'  ❌
'  ✓
'  中
'  é xyz à
'  abc 私 は ん ghi

'  Revert back to the unescaped chars:
sb.Decode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  -----------------------------------------------------------------------------------------
'  HTML decimal character reference

encoding = "unicodeescape-htmldec"
sb.Encode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  Output:
'  🧠
'  🔐
'  ✅
'  ⚠️
'  ❌
'  ✓
'  中
'  é xyz à
'  abc 私 は ん ghi

'  Revert back to the unescaped chars:
sb.Decode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  -----------------------------------------------------------------------------------------
'  Unicode code point notation or U+ notation

encoding = "unicodeescape-plus"
sb.Encode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  Output:
'  u+1f9e0
'  u+1f510
'  u+2705
'  u+26a0u+fe0f
'  u+274c
'  u+2713
'  u+4e2d
'  u+00e9 xyz u+00e0
'  abc u+79c1 u+306f u+3093 ghi

'  Chilkat cannot unescape the Unicode code point notation or U+ notation.
'  For this style, Chilkat only goes in one direction, which is to escape.

'  To emit uppercase hex, specify unicodeescape-plus-upper
encoding = "unicodeescape-plus-upper"
'  ...
'  ...

sb.Clear
sb.AppendSb(sbOriginal)

'  -----------------------------------------------------------------------------------------
'  Hex in Angle Brackets

encoding = "unicodeescape-angle"
sb.Encode(encoding, charsetNotUsed)
Log(sb.GetAsString)

'  Output:
'  <1f9e0>
'  <1f510>
'  <2705>
'  <26a0><fe0f>
'  <274c>
'  <2713>
'  <4e2d>
'  <e9> xyz <e0>
'  abc <79c1> <306f> <3093> ghi

'  Chilkat cannot unescape the angle bracket notation.
'  For this style, Chilkat only goes in one direction, which is to escape.

sb.Clear
sb.AppendSb(sbOriginal)