diff options
Diffstat (limited to 'Doc/Manual/Contract.html')
| -rw-r--r-- | Doc/Manual/Contract.html | 47 |
1 files changed, 25 insertions, 22 deletions
diff --git a/Doc/Manual/Contract.html b/Doc/Manual/Contract.html index 8ecf98486..0001bf9fd 100644 --- a/Doc/Manual/Contract.html +++ b/Doc/Manual/Contract.html @@ -5,13 +5,13 @@ </head> <body bgcolor="#ffffff"> -<a name="n1"></a><H1>10 Contracts</H1> +<H1><a name="Contract"></a>12 Contracts</H1> <!-- INDEX --> <ul> -<li><a href="#n2">The %contract directive</a> -<li><a href="#n3">%contract and classes</a> -<li><a href="#n4">Constant aggregation and %aggregate_check</a> -<li><a href="#n5">Notes</a> +<li><a href="#Contract_nn2">The %contract directive</a> +<li><a href="#Contract_nn3">%contract and classes</a> +<li><a href="#Contract_nn4">Constant aggregation and %aggregate_check</a> +<li><a href="#Contract_nn5">Notes</a> </ul> <!-- INDEX --> @@ -31,8 +31,9 @@ to a declaration. For example, you can easily attach argument checking rules, check the output values of a function and more. When one of the rules is violated by a script, a runtime exception is generated rather than having the program continue to execute. +</p> -<a name="n2"></a><H2>10.1 The %contract directive</H2> +<H2><a name="Contract_nn2"></a>12.1 The %contract directive</H2> Contracts are added to a declaration using the %contract directive. Here @@ -42,9 +43,9 @@ is a simple example: <pre> %contract sqrt(double x) { require: - x >= 0; + x >= 0; ensure: - sqrt >= 0; + sqrt >= 0; } ... @@ -65,24 +66,26 @@ cases, the conditions that must hold must be specified as boolean expressions. <p> In the above example, we're simply making sure that sqrt() returns a non-negative number (if it didn't, then it would be broken in some way). +</p> <p> Once a contract has been specified, it modifies the behavior of the resulting module. For example: +</p> <blockquote> <pre> ->>> example.sqrt(2) +>>> example.sqrt(2) 1.4142135623730951 ->>> example.sqrt(-2) +>>> example.sqrt(-2) Traceback (most recent call last): - File "<stdin>", line 1, in ? -RuntimeError: Contract violation: require: (arg1>=0) ->>> + File "<stdin>", line 1, in ? +RuntimeError: Contract violation: require: (arg1>=0) +>>> </pre> </blockquote> -<a name="n3"></a><H2>10.2 %contract and classes</H2> +<H2><a name="Contract_nn3"></a>12.2 %contract and classes</H2> The <tt>%contract</tt> directive can also be applied to class methods and constructors. For example: @@ -91,14 +94,14 @@ The <tt>%contract</tt> directive can also be applied to class methods and constr <pre> %contract Foo::bar(int x, int y) { require: - x > 0; + x > 0; ensure: - bar > 0; + bar > 0; } %contract Foo::Foo(int a) { require: - a > 0; + a > 0; } class Foo { @@ -127,12 +130,12 @@ In addition to this, separate contracts can be applied to both the base class an <pre> %contract Foo::bar(int x, int) { require: - x > 0; + x > 0; } %contract Spam::bar(int, int y) { require: - y > 0; + y > 0; } class Foo { @@ -153,7 +156,7 @@ In other words conditions specified for the base class and conditions specified for the derived class all must hold. In the above example, this means that both the arguments to <tt>Spam::bar</tt> must be positive. -<a name="n4"></a><H2>10.3 Constant aggregation and %aggregate_check</H2> +<H2><a name="Contract_nn4"></a>12.3 Constant aggregation and %aggregate_check</H2> Consider an interface file that contains the following code: @@ -229,13 +232,13 @@ void move(SomeObject *, int direction, int distance); Regrettably, there is no automatic way to perform similar checks with enums values. Maybe in a future release. -<a name="n5"></a><H2>10.4 Notes</H2> +<H2><a name="Contract_nn5"></a>12.4 Notes</H2> Contract support was implemented by Songyan (Tiger) Feng and first appeared in SWIG-1.3.20. -<p><hr> +<hr> <address>SWIG 1.3 - Last Modified : November 12, 2003</address> </body> |