Nasal Hello World: Difference between revisions
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A simple hello world example in Nasal would be (to be saved in [[$FG_ROOT]]/Nasal): | A simple hello world example in Nasal would be (to be saved in [[$FG_ROOT]]/Nasal): | ||
<syntaxhighlight lang=" | <syntaxhighlight lang="nasal"> | ||
# [[$FG_ROOT]]/Nasal/hello.nas | # [[$FG_ROOT]]/Nasal/hello.nas | ||
print('Hello World!'); | print('Hello World!'); | ||
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Strings in Nasal can also use double quotes which support escaping: | Strings in Nasal can also use double quotes which support escaping: | ||
<syntaxhighlight lang=" | <syntaxhighlight lang="nasal"> | ||
# hello.nas | # hello.nas | ||
print("Hello\nWorld!"); | print("Hello\nWorld!"); | ||
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For example, to print a new line, use: | For example, to print a new line, use: | ||
<syntaxhighlight lang=" | <syntaxhighlight lang="nasal"> | ||
print ("\n"); | print ("\n"); | ||
</syntaxhighlight> | </syntaxhighlight> | ||
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To print a quoted string, use: | To print a quoted string, use: | ||
<syntaxhighlight lang=" | <syntaxhighlight lang="nasal"> | ||
print ("\"quoted string\""); | print ("\"quoted string\""); | ||
</syntaxhighlight> | </syntaxhighlight> | ||
Revision as of 21:09, 10 November 2013
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The FlightGear forum has a subforum related to: Nasal Scripting |
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| Nasal scripting |
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| Nasal internals |
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| Memory Management (GC) |
A simple hello world example in Nasal would be (to be saved in $FG_ROOT/Nasal):
# [[$FG_ROOT]]/Nasal/hello.nas
print('Hello World!');This will show the "Hello World" string during startup in the console window. The hash sign (#) just introduces comments (i.e. will be ignored by the interpreter).
Note: Script-specific symbols such as global variables (or functions) will be put into a scope (namespace) based on the script's name, scripts embedded via aircraft-set.xml files can separately specify a corresponding module name (see Howto: Make an aircraft for details).
Strings in Nasal can also use double quotes which support escaping:
# hello.nas
print("Hello\nWorld!");Double quotes support some of the typical escape sequences:
- \n Newline
- \t Horizontal Tab
- \r Carriage Return
- \\ Backslash
- \" Double quote
- \xyy Hexadecimal-specified character (yy stands for two hexadecimal digits; \x is literal)
For example, to print a new line, use:
print ("\n");To print a quoted string, use:
print ("\"quoted string\"");and so on.
Single quotes treat everything as literal except for embedded single quotes (including embedded whitespace like newlines).
Nasal strings are always arrays of bytes (never characters: see the utf8 library if you want character-based equivalents of substr() et. al.). They can be indexed just like in C (although note that there is no nul termination -- get the length with size()):