Boolean - Revision history

Kevin Reid: copy in tests from E-on-CL scope-univ.updoc r1044

Kevin Reid — Sat, 10 Jan 2009 22:58:47 GMT

copy in tests from E-on-CL scope-univ.updoc r1044

New page

The '''<code>Boolean</code>''' type has exactly two members, <code>false</code> and <code>true</code>. All three of these objects print with those names.

? true
# value: true

? false
# value: false

? boolean
# value: Boolean

The [[universal scope]] contains <code>boolean</code> (no capital), <code>false</code>, and <code>true</code>.

== Protocol ==

{{instance msgdoc|pick|2|<var>t</var>, <var>f</var>|any}}

false.pick(<var>t</var>, <var>f</var>) returns <var>f</var>; true.pick(<var>t</var>, <var>f</var>) returns <var>t</var>.

? true.pick(1, 2)
# value: 1

? false.pick(3, 4)
# value: 4

{{instance msgdoc|not|0||[[Boolean]]}}

Boolean negation.

? !true
# value: false

? !false
# value: true

{{instance msgdoc|or|1|<var>other</var> :[[Boolean]]|[[Boolean]]}}

Boolean or. The argument is coerced to a boolean.

? false | false
# value: false

? false | true
# value: true

? false | def _{to __conformTo(==boolean) :any {return false}}
# value: false

? true | false
# value: true

? true | true
# value: true

? true | -1
# problem: the int -1 doesn't coerce to a boolean

? true | def _{to __conformTo(==boolean) :any {return true}}
# value: true

{{instance msgdoc|and|1|<var>other</var> :[[Boolean]]|[[Boolean]]}}

Boolean and. The argument is coerced to a boolean.

? true & true
# value: true

? true & false
# value: false

? true & def _{to __conformTo(==boolean) :any {return true}}
# value: true

? false & true
# value: false

? false & false
# value: false

? false & -1
# problem: the int -1 doesn't coerce to a boolean

? false & def _{to __conformTo(==boolean) :any {return false}}
# value: false

{{XXX}} discuss ideal default wording of coercion failure errors

{{instance msgdoc|xor|1|<var>other</var> :[[Boolean]]|[[Boolean]]}}

Boolean exclusive or. The argument is coerced to a boolean.

? false ^ false
# value: false

? false ^ true
# value: true

? true ^ def _{to __conformTo(==boolean) :any {return true}}
# value: false

? true ^ false
# value: true

? true ^ true
# value: false

? false ^ -1
# problem: the int -1 doesn't coerce to a boolean

? false ^ def _{to __conformTo(==boolean) :any {return true}}
# value: true

=== op__cmp/1 ===
Comparison with other Booleans. See [[Message op__cmp]].

{{XXX}} write tests for this

[[Category:ELib specification]]

Kevin Reid: use instance msgdoc template

Kevin Reid — Wed, 02 Jul 2008 02:50:49 GMT

use instance msgdoc template

←Older revision		Revision as of 02:50, 2 July 2008
Line 3:		Line 3:
	== Protocol ==		== Protocol ==

-	~~===~~ pick/2 ~~===~~	+	{{instance msgdoc\|pick\|2\|<var>t</var>, <var>f</var>\|any}}
-		+
-	~~pick(~~<var>t</var>, <var>f</var>~~) :~~any	+

	false.pick(<var>t</var>, <var>f</var>) returns <var>f</var>; true.pick(<var>t</var>, <var>f</var>) returns <var>t</var>.		false.pick(<var>t</var>, <var>f</var>) returns <var>f</var>; true.pick(<var>t</var>, <var>f</var>) returns <var>t</var>.

-	~~===~~ not/0 ~~===~~	+	{{instance msgdoc\|not\|0\|\|[[Boolean]]}}
-		+
-	~~not() :~~Boolean	+

	Boolean negation.		Boolean negation.

-	~~===~~ or/1 ~~===~~	+	{{instance msgdoc\|or\|1\|<var>other</var> :[[Boolean]]\|[[Boolean]]}}
-		+
-	~~or(~~<var>other</var> :Boolean~~) :~~Boolean	+

	Boolean or. The argument is coerced to a boolean.		Boolean or. The argument is coerced to a boolean.

-	~~===~~ and/1 ~~===~~	+	{{instance msgdoc\|and\|1\|<var>other</var> :[[Boolean]]\|[[Boolean]]}}
-		+
-	~~and(~~<var>other</var> :Boolean~~) :~~Boolean	+

	Boolean and. The argument is coerced to a boolean.		Boolean and. The argument is coerced to a boolean.

-	~~===~~ xor/1 ~~===~~	+	{{instance msgdoc\|xor\|1\|<var>other</var> :[[Boolean]]\|[[Boolean]]}}
-		+
-	~~xor(~~<var>other</var> :Boolean~~) :~~Boolean	+

	Boolean exclusive or. The argument is coerced to a boolean.		Boolean exclusive or. The argument is coerced to a boolean.

	=== op__cmp/1 ===		=== op__cmp/1 ===
-
	Comparison with other Booleans. See [[Message op__cmp]].		Comparison with other Booleans. See [[Message op__cmp]].

	[[Category:ELib specification]]		[[Category:ELib specification]]

Kevin Reid: category

Kevin Reid — Wed, 02 Jul 2008 02:31:19 GMT

Kevin Reid at 19:47, 21 April 2007

Kevin Reid — Sat, 21 Apr 2007 19:47:42 GMT

←Older revision		Revision as of 19:47, 21 April 2007
Line 1:		Line 1:
-	The '''<code>Boolean</code>''' type has exactly two members, <code>false</code> and <code>true</code>. All three ~~of these objects print with those~~ names.	+	The '''<code>Boolean</code>''' type has exactly two members, <code>false</code> and <code>true</code>. All three names are in the [[universal scope]].

-	~~? true~~	+	== Protocol ==
-	~~# value: true~~	+
-		+
-	~~? false~~	+
-	~~# value: false~~	+
-		+
-	~~? boolean~~	+
-	~~# value: Boolean~~	+

-	~~The [[universal scope]] contains <code>boolean<~~/~~code> (no capital), <code>false</code>, and <code>true</code>.~~	+	=== pick/2 ===

-	~~== Protocol ==~~	+	pick(<var>t</var>, <var>f</var>) :any
-		+
-	~~{{instance msgdoc\|~~pick~~\|2\|~~<var>t</var>, <var>f</var>\|any}}	+

	false.pick(<var>t</var>, <var>f</var>) returns <var>f</var>; true.pick(<var>t</var>, <var>f</var>) returns <var>t</var>.		false.pick(<var>t</var>, <var>f</var>) returns <var>f</var>; true.pick(<var>t</var>, <var>f</var>) returns <var>t</var>.

-	~~? true.pick(1, 2)~~	+	=== not/0 ===
-	~~# value: 1~~	+
-		+	not() :Boolean
-	~~? false.pick~~(~~3, 4~~)	+
-	~~# value~~: 4	+
-		+
-	~~{{instance msgdoc\|not\|0\|\|[[~~Boolean~~]]}}~~	+

	Boolean negation.		Boolean negation.

-	~~? !true~~	+	=== or/1 ===
-	~~# value: false~~	+
-		+
-	~~? !false~~	+
-	~~# value: true~~	+

-	~~{{instance msgdoc\|~~or~~\|1\|~~<var>other</var> :[[Boolean~~]]\|[[~~Boolean~~]]}}~~	+	or(<var>other</var> :Boolean) :Boolean

	Boolean or. The argument is coerced to a boolean.		Boolean or. The argument is coerced to a boolean.

-	~~? false \| false~~	+	=== and/1 ===
-	~~# value: false~~	+
-		+
-	~~? false \| true~~	+
-	~~# value: true~~	+
-		+
-	~~? false \| def _{to __conformTo(~~==~~boolean) :any {return false}}~~	+
-	~~# value: false~~	+
-		+
-	~~? true \| false~~	+
-	~~# value: true~~	+
-		+
-	~~? true \| true~~	+
-	~~# value: true~~	+
-		+
-	~~? true \| -~~1	+
-	~~# problem: the int -1 doesn't coerce to a boolean~~	+
-		+
-	~~? true \| def _{to __conformTo(~~==~~boolean) :any {return true}}~~	+
-	~~# value: true~~	+

-	~~{{instance msgdoc\|~~and~~\|1\|~~<var>other</var> :[[Boolean~~]]\|[[~~Boolean~~]]}}~~	+	and(<var>other</var> :Boolean) :Boolean

	Boolean and. The argument is coerced to a boolean.		Boolean and. The argument is coerced to a boolean.

-	~~? true & true~~	+	=== xor/1 ===
-	~~# value: true~~	+
-		+
-	~~? true & false~~	+
-	~~# value: false~~	+
-		+
-	~~? true & def _{to __conformTo(~~==~~boolean) :any {return true}}~~	+
-	~~# value: true~~	+
-		+
-	~~? false & true~~	+
-	~~# value: false~~	+
-		+
-	~~? false & false~~	+
-	~~# value: false~~	+
-		+
-	~~? false & -~~1	+
-	~~# problem: the int -1 doesn't coerce to a boolean~~	+
-		+
-	~~? false & def _{to __conformTo(~~==~~boolean) :any {return false}}~~	+
-	~~# value: false~~	+

-	~~{{XXX}} discuss ideal default wording of coercion failure errors~~	+	xor(<var>other</var> :Boolean) :Boolean
-		+
-	~~{{instance msgdoc\|~~xor~~\|1\|~~<var>other</var> :[[Boolean~~]]\|[[~~Boolean~~]]}}~~	+

	Boolean exclusive or. The argument is coerced to a boolean.		Boolean exclusive or. The argument is coerced to a boolean.

-	~~? false ^ false~~	+	=== op__cmp/1 ===
-	~~# value: false~~	+
-		+
-	~~? false ^ true~~	+
-	~~# value: true~~	+
-		+
-	~~? true ^ def _{to __conformTo(~~==~~boolean) :any {return true}}~~	+
-	~~# value: false~~	+
-		+
-	~~? true ^ false~~	+
-	~~# value: true~~	+
-		+
-	~~? true ^ true~~	+
-	~~# value: false~~	+
-		+
-	~~? false ^ -~~1	+
-	~~# problem: the int -1 doesn't coerce to a boolean~~	+
-		+
-	~~? false ^ def _{to __conformTo(~~==~~boolean) :any {return true}}~~	+
-	~~# value: true~~	+

-	~~=== op__cmp/1 ===~~
	Comparison with other Booleans. See [[Message op__cmp]].		Comparison with other Booleans. See [[Message op__cmp]].
-
-	~~{{XXX}} write tests for this~~
-
-	~~[[Category:ELib specification]]~~

←Older revision		Revision as of 02:31, 2 July 2008
Line 36:		Line 36:

	Comparison with other Booleans. See [[Message op__cmp]].		Comparison with other Booleans. See [[Message op__cmp]].
		+
		+	[[Category:ELib specification]]