Merge pull request #314 from korpling/docs/update-meta

updated docs

docs/README.md

@@ -1,5 +1,5 @@
 | Type             | Modules                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
 |------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | Import formats   | [conllu](importers/conllu.md), [exmaralda](importers/exmaralda.md), [graphml](importers/graphml.md), [meta](importers/meta.md), [none](importers/none.md), [opus](importers/opus.md), [path](importers/path.md), [ptb](importers/ptb.md), [relannis](importers/relannis.md), [saltxml](importers/saltxml.md), [textgrid](importers/textgrid.md), [toolbox](importers/toolbox.md), [treetagger](importers/treetagger.md), [xlsx](importers/xlsx.md), [xml](importers/xml.md) |
-| Export formats   | [conllu](exporters/conllu.md), [exmaralda](exporters/exmaralda.md), [graphml](exporters/graphml.md), [saltxml](exporters/saltxml.md), [sequence](exporters/sequence.md), [table](exporters/table.md), [textgrid](exporters/textgrid.md), [xlsx](exporters/xlsx.md)                                                                                                                                                                                                          |
+| Export formats   | [conllu](exporters/conllu.md), [exmaralda](exporters/exmaralda.md), [graphml](exporters/graphml.md), [meta](exporters/meta.md), [saltxml](exporters/saltxml.md), [sequence](exporters/sequence.md), [table](exporters/table.md), [textgrid](exporters/textgrid.md), [xlsx](exporters/xlsx.md)                                                                                                                                                                               |
 | Graph operations | [check](graph_ops/check.md), [collapse](graph_ops/collapse.md), [filter](graph_ops/filter.md), [visualize](graph_ops/visualize.md), [enumerate](graph_ops/enumerate.md), [link](graph_ops/link.md), [map](graph_ops/map.md), [revise](graph_ops/revise.md), [time](graph_ops/time.md), [chunk](graph_ops/chunk.md), [split](graph_ops/split.md), [none](graph_ops/none.md)                                                                                                  |

docs/exporters/meta.md

@@ -0,0 +1,63 @@
+# meta (exporter)
+
+This module exports annattos and peppers meta data format.
+Generally all nodes are up for export as a single document,
+thus the `name_key` is used to subset the nodes and define the node names.
+
+Example (with default settings):
+```toml
+[[export]]
+format = "meta"
+path = "..."
+
+[export.config]
+name_key = "annis::doc"
+only = []
+write_ns = false
+```
+
+This is equivalent to:
+```toml
+[[export]]
+format = "meta"
+path = "..."
+
+[export.config]
+```
+
+## Configuration
+
+###  name_key
+
+This key determines the value of the file name and which nodes are being exported into a single file,
+i. e., only nodes that hold a value for the provided will be exported. If values are not unique, an
+already written file will be overwritten.
+
+Example:
+```toml
+[export.config]
+name_key = "my_unique_file_name_key"
+```
+
+###  only
+
+This option allows to restrict the exported annotation keys. Also, adding keys with namespace "annis"
+here is allowed, as annotation keys having that namespace are ignored in the default setting.
+
+Example:
+```toml
+[export.config]
+only = ["annis::doc", "annis::node_name", "annis::node_type", "date"]
+```
+
+###  write_ns
+
+By setting this to true, the namespaces will be exported as well. By default, this option is false.
+
+Example:
+```toml
+[export.config]
+write_ns = "true"
+```
+The namespace will be separated from the annotation name by `::`.
+