Differences between version 7 and revision by previous author of ReversePolish.
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| Newer page: | version 7 | Last edited on Saturday, November 1, 2003 2:28:56 pm | by AristotlePagaltzis | Revert |
| Older page: | version 1 | Last edited on Sunday, February 9, 2003 10:28:24 pm | by GlynWebster | Revert |
@@ -1,35 +1,44 @@
-Style
of syntax used for writing expressions:
+Styles
of syntax used for writing expressions or tree-structured data
:
-*
In __
infix__
notation you write the operator between the arguments.
+
+!!!Infix
+
+
In infix notation you write the operator between the arguments:
c - (5 + a + x) * b
-Infix notation is the usual. It needs precedence rules and/or brackets to make the order of operations unambiguous though
. Polish and Reverse Polish don't have that problem, providing the number arguments to each operator is fixed.
+Infix notation is the usual. It needs precedence rules and/or brackets to make the order of operations unambiguous. Polish and Reverse Polish don't have that problem, providing the number arguments to each operator is fixed.
+
+!!!Reverse Polish
+
+In Reverse Polish, or __postfix__, notation you write the operator after the arguments
.
-* In __Reverse Polish__, or postfix, notation you write the operator after the arguments.
+ c 5 a + x + b
* -
- c 5
a + x + b * -
+It's very easy to interpret expressions in this notation, you need just
a single stack to place intermediate values on, this is why [Forth] uses it.
-It's very easy to interpret expressions in this notation, you need just a single stack to place intermediate values on, this is why [FORTH] uses it.
+!!!Polish
-*
In __
Polish__
, or prefix, notation you write the operator before the arguments.
+In Polish, or __
prefix__
, notation you write the operator before the arguments.
- c * + 5 + a x b
Polish notation is called that because a famous Polish mathematician first used it for Boolean algebra, and nobody can either remember or pronounce his name without looking it up first. (''You'' go look it up.)
+!!!S-expressions
-*
In __
S-exp__
, or [Lisp
], notation you write the operator before the arguments, enclosed in brackets.
+In S-expression
, or [LISP
], notation you write the operator before the arguments, enclosed in brackets:
(- c (* (+ 5 a x) b))
-[Lisp
] operators take any number of arguments so [Lisp
] expressions need brackets to associate arguments with operators.
+[LISP
] operators take any number of arguments so [LISP
] expressions need brackets to associate arguments with operators.
-It's very easy to parse this notation into tree structures, which is why Lisp
uses it.
+It's very easy to parse this notation into tree structures, which is why [LISP]
uses it.
+!!!XML
-*
In __
XML__
notation you bracket the arguments with the operator:
+In XML notation you bracket the arguments with the operator:
<subtract>
<variable name="c"/>
<multiply>
