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1 | ============================== | |||
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2 | The magic commands subsystem | |||
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3 | ============================== | |||
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4 | ||||
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5 | .. warning:: | |||
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6 | ||||
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7 | These are *preliminary* notes and thoughts on the magic system, kept here | |||
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8 | for reference so we can come up with a good design now that the major core | |||
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9 | refactoring has made so much progress. Do not consider yet any part of this | |||
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10 | document final. | |||
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11 | ||||
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12 | Two entry points: | |||
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13 | ||||
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14 | - m.line_eval(self,parameter_s): like today | |||
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15 | - m.block_eval(self,code_block): for whole-block evaluation. | |||
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16 | ||||
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17 | This would allow us to have magics that take input, and whose single line form | |||
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18 | can even take input and call block_eval later (like %cpaste does, but with a | |||
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19 | generalized interface). | |||
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20 | ||||
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21 | Constructor | |||
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22 | =========== | |||
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23 | ||||
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24 | Suggested syntax:: | |||
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25 | ||||
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26 | class MyMagic(BaseMagic): | |||
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27 | requires_shell = True/False | |||
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28 | def __init__(self,shell=None): | |||
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29 | ||||
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30 | ||||
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31 | Registering magics | |||
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32 | ================== | |||
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33 | ||||
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34 | Today, ipapi provides an *expose_magic()* function for making simple magics. | |||
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35 | We will probably extend this (in a backwards-compatible manner if possible) to | |||
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36 | allow the simplest cases to work as today, while letting users register more | |||
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37 | complex ones. | |||
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38 | ||||
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39 | Use cases:: | |||
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40 | ||||
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41 | def func(arg): pass # note signature, no 'self' | |||
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42 | ip.expose_magic('name',func) | |||
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43 | ||||
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44 | def func_line(arg): pass | |||
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45 | def func_block(arg):pass | |||
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46 | ip.expose_magic('name',func_line,func_block) | |||
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47 | ||||
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48 | class mymagic(BaseMagic): | |||
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49 | """Magic docstring, used in help messages. | |||
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50 | """ | |||
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51 | def line_eval(self,arg): pass | |||
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52 | def block_eval(self,arg): pass | |||
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53 | ||||
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54 | ip.register_magic(mymagic) | |||
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55 | ||||
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56 | ||||
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57 | The BaseMagic class will offer common functionality to all, including things | |||
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58 | like options handling (via argparse). | |||
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59 | ||||
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60 | ||||
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61 | Call forms: line and block | |||
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62 | ========================== | |||
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63 | ||||
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64 | Block-oriented environments will call line_eval() for the first line of input | |||
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65 | (the call line starting with '%') and will then feed the rest of the block to | |||
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66 | block_eval() if the magic in question has a block mode. | |||
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67 | ||||
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68 | In line environments, by default %foo -> foo.line_eval(), but no block call is | |||
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69 | made. Specific implementations of line_eval can decide to then call block_eval | |||
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70 | if they want to provide for whole-block input in line-oriented environments. | |||
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71 | ||||
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72 | The api might be adapted for this decision to be made automatically by the | |||
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73 | frontend... | |||
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74 | ||||
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75 | ||||
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76 | Precompiled magics for rapid loading | |||
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77 | ==================================== | |||
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78 | ||||
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79 | For IPython itself, we'll have a module of 'core' magic functions that do not | |||
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80 | require run-time registration. These will be the ones contained today in | |||
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81 | Magic.py, plus any others we deem worthy of being available by default. This | |||
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82 | is a trick to enable faster startup, since once we move to a model where each | |||
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83 | magic can in principle be registered at runtime, creating a lot of them can | |||
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84 | easily swamp startup time. | |||
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85 | ||||
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86 | The trick is to make a module with a top-level class object that contains | |||
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87 | explicit references to all the 'core' magics in its dict. This way, the magic | |||
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88 | table can be quickly updated at interpreter startup with a single call, by | |||
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89 | doing something along the lines of:: | |||
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90 | ||||
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91 | self.magic_table.update(static_magics.__dict__) | |||
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92 | ||||
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93 | The point will be to be able to bypass the explicit calling of whatever | |||
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94 | register_magic() API we end up making for users to declare their own magics. | |||
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95 | So ultimately one should be able to do either:: | |||
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96 | ||||
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97 | ip.register_magic(mymagic) # for one function | |||
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98 | ||||
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99 | or:: | |||
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100 | ||||
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101 | ip.load_magics(static_magics) # for a bunch of them | |||
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102 | ||||
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103 | I still need to clarify exactly how this should work though. |
@@ -1,19 +1,20 b'' | |||||
1 | .. _developer_guide: |
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1 | .. _developer_guide: | |
2 |
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2 | |||
3 | ========================= |
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3 | ========================= | |
4 | IPython developer's guide |
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4 | IPython developer's guide | |
5 | ========================= |
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5 | ========================= | |
6 |
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6 | |||
7 | .. toctree:: |
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7 | .. toctree:: | |
8 | :maxdepth: 1 |
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8 | :maxdepth: 1 | |
9 |
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9 | |||
10 | contributing.txt |
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10 | contributing.txt | |
11 | coding_guide.txt |
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11 | coding_guide.txt | |
12 | doc_guide.txt |
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12 | doc_guide.txt | |
13 | testing.txt |
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13 | testing.txt | |
14 | release.txt |
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14 | release.txt | |
15 | roadmap.txt |
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15 | roadmap.txt | |
16 | reorg.txt |
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16 | reorg.txt | |
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17 | magic_blueprint.txt | |||
17 | notification_blueprint.txt |
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18 | notification_blueprint.txt | |
18 | ipgraph.txt |
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19 | ipgraph.txt | |
19 |
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20 |
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