# Running in world age ... while current world is

**URL:** <https://discourse.julialang.org/t/running-in-world-age-while-current-world-is/23113>\
**Category:** General Usage\
**Tags:** world\_age\
**Created:** [April 13, 2019, 3:42pm UTC](https://discourse.julialang.org/t/running-in-world-age-while-current-world-is/23113 "2019-04-13T15:42:26Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [April 14, 2019, 2:24am UTC](https://discourse.julialang.org/t/running-in-world-age-while-current-world-is/23113/4 "2019-04-14T02:24:49Z")

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This usually means that you are using `eval` to define new functions inside your function and then trying to call them. See the explanation here: [Help calling a function defined from expressions - #4 by stevengj](https://discourse.julialang.org/t/help-calling-a-function-defined-from-expressions/1340/4)

Calling `eval` inside a function is _almost_ always the wrong thing to do. Often new Julia programmers make the mistake of trying to build up inner functions from strings or symbolic expressions that they `eval`, when the right thing is to just pass/define functions directly using `->`.

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