plantuml_in_knitr.Rmd

---
title: "plantuml test"
author: "Rainer M Krug"
date: "6/17/2020"
output: html_document
---

```{r setup, include=FALSE}
library(plantuml)
knitr::knit_engines$set(
  plantuml = function(options) {
    code <- paste(options$code, collapse = "\n")
    if (options$eval) {
      #
      puml <- plantuml(code)
      if (is.null( options$plantuml.format )) {
        fig_type <- "png" 
      } else {
        fig_type <- options$plantuml.format
      }
      fig <- paste0(options$label, ".", fig_type)
      #
      tmp_fig <- tempfile(fileext = fig)
      plot(
        x = puml, 
        file = fig
      )
      file.copy(tmp_fig, fig)
      out <- list(knitr::include_graphics(fig))
      knitr::engine_output(
        options = options, 
        out = out
      )
    } else {
      out <- NULL
      knitr::engine_output(
        options = options, 
        code = code, 
        out = out
      )
    }
  }
)
```

## R Markdown
```{plantuml tut, eval = FALSE, plantuml.format = "svg"}
@startuml


start
''''''''''''
:= Install and load the `dmdScheme` package in R
..R..
""install.packages("dmdScheme")""
""library("dmdScheme")""|
:= Start the included shiny app
..R..
""run_app()""|
''''''''''''
:= Select scheme 
..BROWSER..
""Availabe dmdSchemes"";
''''''''''''
:= Download New Scheme
..BROWSER..;
''''''''''''
repeat
  := Enter / Edit metadata in downloaded xlsx
  ..Excel, Pages, Libre Office, Google Docs, etc..;
  := Upload Spreadsheet containig Metadata
  ..BROWSER..|
  := Upload Datafiles
  ..BROWSER..|
  := Validate metadata and create report
  ..BROWSER..;
repeat while (errors or warnings?) is (yes)
-> no;
''''''''''''
:= Export Uploaded Spreadsheet to xml
..BROWSER..;
''''''''''''
stop

@enduml

```