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Add README
Signed-off-by: Tobias Deiminger <tobias.deiminger@linutronix.de>
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‎README.md‎

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# Exploring possibilities for integrating StrictDoc with ELISA’s requirements template approach for the Linux kernel
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This demonstrates how to realize the tool-agnostic
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[ELISA Kernel Requirements Template](https://docs.google.com/document/d/1c7S7YAledHP2EEQ2nh26Ibegij-XPNuUFkrFLtJPlzs/edit?tab=t.0)
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proposal by using [StrictDoc](https://strictdoc.readthedocs.io) as requirements processing tool. The repository contains a filtered (for brevity)
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copy of the Linux kernel with requirements and tests from Alessandro Carminat and Gabriele Paoloni ([^1], [^2]) applied on top. ELISA's
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[`SPDX-*` tagging scheme]((https://docs.google.com/document/d/1c7S7YAledHP2EEQ2nh26Ibegij-XPNuUFkrFLtJPlzs/edit?tab=t.0#heading=h.9dudo2y6dlhf))
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was [added](https://github.com/strictdoc-project/linux-strictdoc/commit/9df9595b) along
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with a minimal StrictDoc project configuration.
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[^1]: https://lore.kernel.org/all/20250910170000.6475-1-gpaoloni@redhat.com/
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[^2]: https://lore.kernel.org/linux-trace-kernel/20250814122206.109096-1-gpaoloni@redhat.com/#r
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Go to [rendered requirements](https://strictdoc-project.github.io/linux-strictdoc/).
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## Demonstrated features
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- Use `strictdoc export .` to generate a nice
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[static HTML document tree](https://strictdoc-project.github.io/linux-strictdoc/linux-strictdoc/Documentation/requirements/charmisc.html)
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with visual representation of the
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[traceability graph](https://strictdoc-project.github.io/linux-strictdoc/linux-strictdoc/Documentation/requirements/charmisc-TRACE.html#DOC-SUBSYS-CHARMISC),
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validation results and full-text search. Other output formats as e.g. PDF are available.
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- Compile and validate requirements
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[in CI](https://github.com/strictdoc-project/linux-strictdoc/blob/lpc25/.github/workflows/ci.yaml).
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- Parses source code
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[SPDX-Req-* tags proposed by ELISA](https://docs.google.com/document/d/1c7S7YAledHP2EEQ2nh26Ibegij-XPNuUFkrFLtJPlzs/edit?tab=t.0#heading=h.9dudo2y6dlhf)
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and translates them to StrictDocs internal model.
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- Sidecar: Proposed by ELISA to hold additional requirement meta data outside source code. Realized as
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[separate sdoc file](https://github.com/strictdoc-project/linux-strictdoc/blob/lpc25/Documentation/requirements/tracing.sdoc)s
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containing requirement stubs. Stubs are merged with source code tags by matching on `SPDX-Req-ID`.
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- Use `strictdoc manage auto-assign` to generate SPDX-Req-ID and SPDX-Req-HKey as suggested by Linux kernel
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requirements template. The hash generation method is `echo -nE "${PROJECT}${FILE_PATH}${INSTANCE}${CODE}" | sha256sum`.
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See [commit 86e7810d](https://github.com/strictdoc-project/linux-strictdoc/commit/86e7810d)
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for the auto-generated changes.
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- Tracing: Requirements, tests and functions become individual nodes in the traceability graph and are connected
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by their stable IDs.
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- Custom validations: Use plugin API to
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[provide a check](https://github.com/strictdoc-project/linux-strictdoc/blob/lpc25/tools/requirements/validation_plugin.py#L28)
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to see if each requirement has at least one associated test, and each function expectations has at least one dedicated
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test.
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- Drift detection: As kernel development goes on, occasionally rerun `strictdoc manage auto-assign`. If `SPDX-Req-HKey`
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changes, this means that some semantic aspect of the requirement may have changed.
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For a thorough documentation of StrictDocs features see
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[StrictDoc User Guide ](https://strictdoc.readthedocs.io/en/stable/stable/docs/strictdoc_01_user_guide.html)
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Experiments unrelated to StrictDoc:
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- Semantic search for LLR candidates:
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There should be consensus which functions are "most valuable" to document.
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Coccinelle allows to
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[document that consensus](https://github.com/strictdoc-project/linux-strictdoc/blob/lpc25/scripts/coccinelle/docs/)
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in a machine readable and executable way.
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## Tutorial: Add a Requirement
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### Install StrictDoc
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```sh
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pipx install strictdoc # note: requires strictdoc >= 0.15.1
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git clone https://github.com/strictdoc-project/linux-strictdoc
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cd linux-strictdoc
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```
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### Edit
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Add requirement statement and temporary identifier to source code comment
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`kernel/trace/trace_events.c`
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```c
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/*
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* SPDX-Req-ID: TMP-trace_events_enabled
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* SPDX-Req-Text:
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* This function shall check if there are enabled events in the provided list.
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*
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* Returns:
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* 0 : no events exist?
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* 1 : all events are disabled
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* 2 : all events are enabled
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* 3 : some events are enabled and some are enabled
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*/
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int trace_events_enabled(struct trace_array *tr, const char *system)
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```
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Add corresponding requirement stub in sidecar file
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`Documentation/requirements/tracing.sdoc`
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```
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[REQUIREMENT]
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MID: TMP-trace_events_enabled
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TITLE: trace_events_enabled
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```
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### Finish
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Calculate stable identifier and hash value, will be replaced inline
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```sh
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strictdoc manage auto-uid .
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```
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Verify new hash values were added and no existing requirement was changed
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```sh
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git diff
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```
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```diff
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diff --git a/Documentation/requirements/tracing.sdoc b/Documentation/requirements/tracing.sdoc
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index 8d1dd2b5..2d86384a 100644
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--- a/Documentation/requirements/tracing.sdoc
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+++ b/Documentation/requirements/tracing.sdoc
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@@ -22,6 +22,11 @@ TITLE: Event Tracing
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MID: 1ac497acf75d497f893006853f85fe86
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TITLE: Requirements
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+[REQUIREMENT]
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+MID: b12884ce9b5b3258f1d28026c8aa1526f94030fd9f61ba583560f472015b1abb
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+HASH: 5949e5bf7ec43ed2c665d4ffe614dfaa285aafbe73a77df55aef0c099637f65b
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+TITLE: trace_events_enabled
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+
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[REQUIREMENT]
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MID: 77958d2a51762caa727e5751d8dfec127c07cb5385f542d7b2fdf26b2a07c8b3
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HASH: e8ee84ca42f5626ca9636abb53ded027708fdaabc99c8b935c016dda53130d81
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diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
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index 16dabd1f..d07db4fa 100644
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--- a/kernel/trace/trace_events.c
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+++ b/kernel/trace/trace_events.c
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@@ -2062,6 +2062,9 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
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}
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/*
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+ * SPDX-Req-ID: b12884ce9b5b3258f1d28026c8aa1526f94030fd9f61ba583560f472015b1abb
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+ * SPDX-Req-Text: This function shall check if there are enabled events in the provided list.
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+ *
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* Returns:
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* 0 : no events exist?
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* 1 : all events are disabled
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```
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Verify and validate
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```sh
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strictdoc export .
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```
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### Send for Review
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```sh
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git add -u && git commit -m "docs: Add LLR for trace_events_enabled"
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git format-patch -n1
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```
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## Explanation of Content and Processing
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```
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.
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├── Documentation
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│ └── requirements
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│ ├── charmisc.sdoc # sidecar
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│ └── tracing.sdoc # sidecar
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├── drivers
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│ └── char
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│ └── mem.c # Linux code with inlined LLRs
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├── kernel
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│ └── trace
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│ └── trace_events.c # Linux code with inlined LLRs
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├── scripts
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│ └── coccinelle
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│ └── docs
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│ └── *.cocci # SmPL to discover LLR candidates
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├── strictdoc_config.py # StrictDoc project configuration
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└── tools
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├── requirements
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│ └── validation_plugin.py # custom requirement validations
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└── testing
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└── selftests
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└── devmem
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└── tests.c # tests for /dev/mem LLRs
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```
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StrictDoc performs the following notable process steps:
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- parse \*.sdoc files to create the initial traceability index (a DAG structure)
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- parse \*.c files using tree-sitter, read SPDX tags from it and merge it into the DAG
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- perform built-in validations and calculate built-in statistics
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- perform custom validations
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* check if all requirements have at least one related test
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* check if all function expectations are mentioned by one related test
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- render the DAG into a HTML document tree where all nodes are traceable, including
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requirements text, visual graph representation and source code view
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## Handling Fields with Special Meaning but Different Name in StrictDoc / ELISA
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The StrictDoc model assigns special meaning to some reserved field names:
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- `UID` Unique, human-readable. May change during requirement life-cycle. Used to refer to child/parents by default.
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- `MID`: Unique, not human-readable, stable. Optionally used to refer to child/parents.
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Supports changing the human-readable UID during the requirement life-cycle.
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- `HASH`: Hash sum over predefined requirement content. Can be auto-calculated.
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- `STATEMENT`: Some document views and import/export formats require to select a "most important"
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field from the many fields.
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- `COMMENT`: Can occur multiple times within one requirement.
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The ELISA requirements template defines similar special meaning for fields, but under different name.
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This is solved by two StrictDoc features:
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- `ProjectConfig(source_nodes=[SourceNodesEntry(sdoc_to_source_map={<sdoc_name>: <elisa_name>, ...})])` let's you define
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a mapping for fields that appearing under a different name in source code tags.
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Example: The stable ID appears as `SPDX-Req-ID` in source code comments, but must be named `MID` in sdoc.
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- Setting `HUMAN_TITLE` in the grammar lets you define a different display name for a field that has special
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StrictDoc meaning. Example: ELISA wants `HASH` to be named `SPDX-Req-HKey`. Since the field appears only in sdoc,
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but not in source code, it's enough to define `HUMAN_TITLE: SPDX-Req-HKey` for the `HASH` field.
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`sdoc_to_source_map` is not needed in this case.

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