src/bookofnim/deepdives/templateMacros

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templates and macros

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TLDR

  • pretty much skipped the entire section on templates, and definitely on macros
  • FYI: you dont know nim if you dont know templates & macros

TODOs

templates

  • simple form of a macro
  • supports lazy evaluation
  • enables raw code substitution on nim's abstract syntax tree
  • are processed in the semantic pass of the compiler
  • accepts meta types

template types

  • untyped an expression thats not resolved for lazy evaluation
  • typed an expression that is resolved for greedy evaluation

macros

  • an API for metaprogramming

Vars

xy = 4
Source   Edit  

Lets

theyAskedNickely`gensym4 = true
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theyAskedNickely`gensym5 = false
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Consts

debug = true
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loc`gensym2 = (filename: "templateMacros.nim", line: 51, column: 6)
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ploc`gensym2 = "templateMacros.nim(51, 7)"
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Procs

proc logEager(msg: string) {.inline, ...raises: [IOError], tags: [WriteIOEffect],
                             forbids: [].}
msg arg is evaluted before the fn is evoked Source   Edit  

Templates

template `!=`(a, b: untyped): untyped
it will replace a & b with the a and b operands to != then replace a != b in the original with the below template i.e. assert(5 != 6) -> assert(not (5 == 6)) Source   Edit   
template blockRunner(please: bool; body: untyped): void
example of using untyped to get a block of statements the block statements are bound to the body param Source   Edit   
template logLazy(msg: string)
the template is processed before msg arg so if debug is false, msg wont be evaluted Source   Edit  

Made with Nim. Generated: 2023-04-29 13:01:07 UTC