Procyon ember at 01:57, 22 February 2016

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Procyon ember at 19:54, 21 February 2016

2016-02-21T19:54:48Z

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2013-01-27T02:55:53Z

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calc

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Calc comes with [[GNU Emacs]] starting with version 22.

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 </source>
-'''Note:''' The shell example uses ''message'' to cause the result to be printed. In ''-batch'' mode, ''message'' prints to standard output. In emacs lisp, printing is a [https://en.wikipedia.org/wiki/Side_effect_%28computer_science%29 side effect] which only occurs when you ask for it. ''IELM'' displays evaluation results as a convenience, and ''*scratch*'' only inserts evaluation results depending on how you invoke it (such as with [https://www.gnu.org/software/emacs/manual/html_node/emacs/Lisp-Interaction.html#Lisp-Interaction eval-print-last-sexp]). ''message'' doesn't preserve quotation marks around strings because its output is intended for humans, not the lisp reader.
+'''Note:''' The shell examples use ''message'' to cause the evaluation result to be printed. In emacs lisp, printing is a [https://en.wikipedia.org/wiki/Side_effect_%28computer_science%29 side effect] which only occurs when you ask for it. ''IELM'' displays the result as a convenience, and ''*scratch*'' only inserts then result depending on how you invoke it (such as with [https://www.gnu.org/software/emacs/manual/html_node/emacs/Lisp-Interaction.html#Lisp-Interaction eval-print-last-sexp]). ''message'' doesn't preserve quotation marks around strings because its output is intended for humans, not the lisp reader. In ''-batch'' mode, ''message'' prints to standard error, but ''print'' could be used to direct results to standard output.
 === lists ===

← Older revision		Revision as of 19:54, 21 February 2016
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	[http://www.emacswiki.org/emacs/CategoryCalculators Category Calculators -Emacs Wiki-]		[http://www.emacswiki.org/emacs/CategoryCalculators Category Calculators -Emacs Wiki-]
		+
		+	== from emacs lisp via calc-eval ==
		+
		+	Calc may be invoked from [[Emacs_Lisp]] via [https://www.gnu.org/software/emacs/manual/html_node/calc/Calling-Calc-from-Your-Programs.html#Calling-Calc-from-Your-Programs calc-eval]. Try these examples in a ''scratch'' or [[IELM]] buffer, or via a shell one-liner in [https://www.gnu.org/software/emacs/manual/html_node/emacs/Initial-Options.html#Initial-Options batch mode].
		+
		+	=== using calc-eval ===
		+
		+	''calc-eval'' accepts a string containing an [https://www.gnu.org/software/emacs/manual/html_node/calc/Algebraic-Entry.html#Algebraic-Entry algebraic expression] as its first argument, and returns the result of evaluating the expression in a string.
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval "sqrt(2 ^ 16)"))
		+	;; ==> "256"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval "sqrt(2 ^ 16)"))'
		+	# ==> 256
		+	</source>
		+
		+	=== floating point numbers ===
		+
		+	[https://www.gnu.org/software/emacs/manual/html_node/calc/Floats.html#Floats Floats] default to 12 digits of [https://www.gnu.org/software/emacs/manual/html_node/calc/Precision.html#Precision precision], with the final digit rounded.
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval (calc-eval "2 / 3")
		+	;; ==> "0.666666666667"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval "2 / 3"))'
		+	# ==> 0.666666666667
		+	</source>
		+
		+	'''Note:''' The shell example uses ''message'' to cause the result to be printed. In ''-batch'' mode, ''message'' prints to standard output. In emacs lisp, printing is a [https://en.wikipedia.org/wiki/Side_effect_%28computer_science%29 side effect] which only occurs when you ask for it. ''IELM'' displays evaluation results as a convenience, and ''scratch'' only inserts evaluation results depending on how you invoke it (such as with [https://www.gnu.org/software/emacs/manual/html_node/emacs/Lisp-Interaction.html#Lisp-Interaction eval-print-last-sexp]). ''message'' doesn't preserve quotation marks around strings because its output is intended for humans, not the lisp reader.
		+
		+	=== lists ===
		+
		+	If the string is a comma-delimited list of expressions, then a comma-delimited list of results will be returned.
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval "9 / 5, trunc(9 / 5), 9 % 5")
		+	;; ==> "1.8, 1, 4"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval "9 / 5, trunc(9 / 5), 9 % 5"))'
		+	# ==> 1.8, 1, 4
		+	</source>
		+
		+	=== random numbers ===
		+
		+	[https://www.gnu.org/software/emacs/manual/html_node/calc/Random-Numbers.html#Random-Numbers Calc's random number generator] is seeded from the system time when calc is started. ''random(N)'' returns a non-negative integer less than ''N''. Your results should vary from the examples below.
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval "1 + random(6), 1 + random(6), 1 + random(6)")
		+	;; ==> "1, 4, 3"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval "1 + random(6), 1 + random(6)"))'
		+	# ==> 5, 2
		+	</source>
		+
		+	=== fractions ===
		+
		+	[https://www.gnu.org/software/emacs/manual/html_node/calc/Fractions.html#Fractions Fractions] are written as ''NUMERATOR:DENOMINATOR'' to distinguish them from divison operations. Mixed fractions may be entered as ''WHOLE:NUMERATOR:DENOMINATOR''. Fraction results are reduced to lowest terms, and may be improper fractions.
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval "2:1:4 + 1:2")
		+	;; ==> "11:4"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval "2:1:4 + 1:2"))'
		+	# ==> 11:4
		+	</source>
		+
		+	=== entering non-decimal integers ===
		+
		+	[https://www.gnu.org/software/emacs/manual/html_node/calc/Integers.html#Integers integers] may be entered as ''RADIX#VALUE'', where ''RADIX'' may range from 2 to 36 inclusive.
		+
		+	'''Caution!''' This is '''not''' the same [https://www.gnu.org/software/emacs/manual/html_node/elisp/Integer-Basics.html#Integer-Basics notation used by emacs lisp].
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval "2#10 * 8#10")
		+	;; ==> "16"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval "2#10 * 8#10"))'
		+	# ==> 16
		+	</source>
		+
		+	== advanced calc-eval ==
		+
		+	If the first argument to ''calc-eval'' is a list, then the first element of the list should be an algebraic expression in a string. Remaining elements of the list are zero or more ''NAME VALUE'' pairs which specify [https://www.gnu.org/software/emacs/manual/html_node/calc/Mode-Settings.html#Mode-Settings mode settings].
		+
		+	'''Important:''' In emacs lisp <nowiki>'(foo)</nowiki> is a [https://www.gnu.org/software/emacs/manual/html_node/elisp/Quoting.html#Quoting quoted] list, but <nowiki>'</nowiki> (apostrophe) is special to the shell. Lisp expressions in previous shell examples were wrapped in <nowiki>'</nowiki> (apostrophe) symbols to prevent the shell from interpreting them. In the following shell examples, ''(quote (foo bar))'' makes a quoted list without breaking the [https://www.gnu.org/software/bash/manual/html_node/Quoting.html#Quoting shell quoting].
		+
		+	=== non-decimal integer results ===
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval '("2 * 8" calc-number-radix 16))
		+	;; ==> "16#10"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval (quote ("20" calc-number-radix 16))))'
		+	# ==> 16#14
		+	</source>
		+
		+	=== setting numeric precision ===
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval '("2 / 3" calc-internal-prec 20))
		+	;; ==> "0.66666666666666666667"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval (quote ("2 / 3" calc-internal-prec 20))))'
		+	# ==> 0.66666666666666666667
		+	</source>
		+
		+	=== setting angular mode ===
		+
		+	<source lang=lisp>
		+	;; emacs lisp
		+	(calc-eval '("arctan2(0, -1)" calc-internal-prec 20 calc-angle-mode rad))
		+	;; ==> "3.1415926535897932385"
		+	</source>
		+
		+	<source lang=bash>
		+	# shell
		+	emacs -Q -batch --eval='(message "%s" (calc-eval (quote ("arctan2(0, -1)" calc-angle-mode rad))))'
		+	# ==> 3.14159265359
		+	</source>

← Older revision		Revision as of 02:55, 27 January 2013
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	Calc comes with [[GNU Emacs]] starting with version 22.		Calc comes with [[GNU Emacs]] starting with version 22.
		+
		+	[http://www.gnu.org/software/emacs/manual/html_mono/calc.html The GNU Emacs Calculator]
		+
		+	[http://www.emacswiki.org/emacs/CategoryCalculators Category Calculators -Emacs Wiki-]

Calc - Revision history

Procyon ember at 01:57, 22 February 2016

Procyon ember at 19:54, 21 February 2016

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