ci: generate html documentation

.gitlab-ci.yml

@@ -49,7 +49,7 @@ Check style:
   script:
     - pre-commit run --show-diff-on-failure --color=always --all-files
   tags:
-    -  alpine
+    - alpine
   rules:
     - if: $CI_PIPELINE_SOURCE == "web"
       when: manual
@@ -335,3 +335,39 @@ Check with NAG 7.1.7114 (CMake, Unix Makefiles):
     - !reference [.check_nag, before_script]
     # nagfor is supposed to use non-default gcc:
     - export FFLAGS="-Wc=`which gcc` $FFLAGS"
+
+.common_html:
+  variables:
+    BUILD_DIRECTORY: ${CI_PROJECT_DIR}/build
+    HTML_BUILD_DIRECTORY: ${BUILD_DIRECTORY}/doc/html
+
+Generate HTML pages:
+  extends: .common_html
+  before_script:
+    - apk add cmake gcc gfortran musl-dev
+  script:
+    - >
+      cmake
+      -S "${CI_PROJECT_DIR}"
+      -B "${BUILD_DIRECTORY}"
+      -DCMAKE_C_COMPILER=gcc
+      -DCMAKE_Fortran_COMPILER=gfortran
+      -DBUILD_TESTING:BOOL=OFF
+      -DMTIME_ENABLE_FORTRAN_HL:BOOL=OFF
+      -DMTIME_ENABLE_PYTHON:BOOL=OFF
+      -DMTIME_BUILD_EXAMPLES:BOOL=OFF
+      -DMTIME_BUILD_DOCS:BOOL=ON
+      -DDOXYGEN_GENERATE_LATEX:BOOL=OFF
+      -DDOXYGEN_GENERATE_MAN:BOOL=OFF
+      -DDOXYGEN_GENERATE_HTML:BOOL=ON
+    - cmake --build "${BUILD_DIRECTORY}" --target doc
+  tags:
+    - doxygen
+  rules:
+    - if: $CI_PIPELINE_SOURCE == "web"
+      when: manual
+    - when: always
+  interruptible: true
+  artifacts:
+    paths:
+      - ${HTML_BUILD_DIRECTORY}