Difference between revisions of "Macro Functions"

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(formatting + added another example from @perrochon)
m (Text replacement - "</source>" to "</syntaxhighlight>")
 
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=== <translate>Description</translate> ===
 
=== <translate>Description</translate> ===
 
Macro Functions receive a list of tokens and output a string which will be pasted into code at compile time.
 
Macro Functions receive a list of tokens and output a string which will be pasted into code at compile time.
<source lang="lua">
+
<syntaxhighlight lang="lua">
 
name @ (| ...body... |)
 
name @ (| ...body... |)
</source>
+
</syntaxhighlight>
  
 
You should use parenthesis around markers - '|' is the preferred marker.
 
You should use parenthesis around markers - '|' is the preferred marker.
Line 20: Line 20:
  
 
You can redefine a macro with @@:
 
You can redefine a macro with @@:
<source lang="lua">
+
<syntaxhighlight lang="lua">
 
name @@ (| ...another_body... |)
 
name @@ (| ...another_body... |)
</source>
+
</syntaxhighlight>
  
 
To call macro function use its name with parenthesis as with usual functions:
 
To call macro function use its name with parenthesis as with usual functions:
<source lang="lua">
+
<syntaxhighlight lang="lua">
 
name(...arguments...)
 
name(...arguments...)
</source>
+
</syntaxhighlight>
  
 
=== <translate>Examples</translate> ===
 
=== <translate>Examples</translate> ===
 
'''Enumeration'''
 
'''Enumeration'''
<source lang="lua">
+
<syntaxhighlight lang="lua">
 
enum @ (|
 
enum @ (|
 
local t = ...
 
local t = ...
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enum(apple, orange, melon)
 
enum(apple, orange, melon)
print(apple, orange, melon) --> 1 2 3</source>
+
print(apple, orange, melon) --> 1 2 3</syntaxhighlight>
  
 
'''Turning off the print command'''
 
'''Turning off the print command'''
<source lang="lua">
+
<syntaxhighlight lang="lua">
 
print @ (| return "" |)
 
print @ (| return "" |)
</source>
+
</syntaxhighlight>
  
 
'''Unroll loops'''
 
'''Unroll loops'''
<source lang="lua">
+
<syntaxhighlight lang="lua">
 
dotimes @ (|
 
dotimes @ (|
 
local times = table.remove(..., 1)
 
local times = table.remove(..., 1)
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dotimes(10 print "Boom!")
 
dotimes(10 print "Boom!")
</source>
+
</syntaxhighlight>
  
 
'''A Sum macro example'''
 
'''A Sum macro example'''
<source lang="lua">
+
<syntaxhighlight lang="lua">
-- comma counts as an argument meaning SUM(o1, o2) has three parameters
+
-- comma counts as an argument meaning MYSUM(o1, o2) has three parameters
SUM @ (| return "("..(...)[1] + (...)[3] ..")" |)
+
MYSUM @ (| return "("..(...)[1] + (...)[3] ..")" |)
print (SUM(1,2) * SUM(3,1))
+
print (MYSUM(1,2) * MYSUM(3,1))
</source>
+
</syntaxhighlight>
  
 
{|-
 
{|-
 
| style="width: 50%; vertical-align:top;"|
 
| style="width: 50%; vertical-align:top;"|
 +
 
=== <translate>Methods</translate> ===
 
=== <translate>Methods</translate> ===
 
| style="width: 50%; vertical-align:top;"|
 
| style="width: 50%; vertical-align:top;"|

Latest revision as of 14:31, 13 July 2023


Supported platforms: Platform android.pngPlatform ios.pngPlatform mac.pngPlatform pc.png
Available since: Gideros 2017.10

Description

Macro Functions receive a list of tokens and output a string which will be pasted into code at compile time.

name @ (| ...body... |)

You should use parenthesis around markers - '|' is the preferred marker.

The same marker should be used to close macro body with closing parenthesis right after it.

You can use any of these markers:

\`~ ! # $ % ^ & * / + = |

You can redefine a macro with @@:

name @@ (| ...another_body... |)

To call macro function use its name with parenthesis as with usual functions:

name(...arguments...)

Examples

Enumeration

enum @ (|
	local t = ...
	local r = {}
	for i = 1, #t, 2 do
		table.insert(r, t[i] .. " @ " .. i // 2 + 1)
	end
	print(table.concat(r, " "))
	return table.concat(r, " ")
|)

enum(apple, orange, melon)
print(apple, orange, melon) --> 1 2 3

Turning off the print command

print @ (| return "" |)

Unroll loops

dotimes @ (|
	local times = table.remove(..., 1)
	return (table.concat(..., " ").." "):rep(times)
|)

local t = {}

dotimes(10 print "Boom!")

A Sum macro example

-- comma counts as an argument meaning MYSUM(o1, o2) has three parameters
MYSUM @ (| return "("..(...)[1] + (...)[3] ..")" |)
print (MYSUM(1,2) * MYSUM(3,1))

Methods

Events

Constants