Erlang (programming language)/Tutorials/Advanced syntax: Difference between revisions
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imported>Eric Evers No edit summary |
imported>Eric Evers No edit summary |
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There are some strange | There are some strange elements of erlang syntax, some of which are caused by the | ||
needs of parallel programming and functional programming. | needs of parallel programming and functional programming. | ||
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Guard expressions are restricted to only builtin functions. This is | Guard expressions are restricted to only builtin functions. This is | ||
generally not a problem becuase | generally not a problem becuase one can precalculate values from non-builtin functions | ||
before the guard and then use the value in the guard expression. | before the guard and then use the value in the guard expression. | ||
Restricting functions in guards protects from side effects and may increase | Restricting functions in guards protects from side effects and may increase | ||
speed. | speed. | ||
Revision as of 18:44, 1 September 2008
There are some strange elements of erlang syntax, some of which are caused by the needs of parallel programming and functional programming.
Each 'if' structure must have a true conditional branch. If a variable is assigned(matched) in one branch of an 'if' or 'case' sturcture and used after that structure then the variable must be assigned(matched) in all the branches.
Guard expressions are restricted to only builtin functions. This is generally not a problem becuase one can precalculate values from non-builtin functions before the guard and then use the value in the guard expression. Restricting functions in guards protects from side effects and may increase speed.