Defining functions in text processed by the StreamingTemplateEngine

Hi,

I am trying to use the StreamingTemplateEngine to create dynamic 
markdown (similarly to the rmd (r markdown, 
https://rmarkdown.rstudio.com/authoring_quick_tour.html) but I've 
encountered a snag:

Simple usage such as the following works fine using the 
StreamingTemplateEngine:

def text = """\ <% def now = java.time.LocalDate.now() %> # Hello Today 
(<%= now.getDayOfWeek().getDisplayName(java.time.format.TextStyle.FULL, 
java.util.Locale.getDefault()) %>) is <%= java.time.LocalDate.now() %>. 
The weather in next 3 days will be: <% def weather = [ "Sunny", "Rainy", 
"Cloudy", "Windy" ] for (i = 1; i < 4; i++) { def day = now.plusDays(i) 
def dayName = 
day.getDayOfWeek().getDisplayName(java.time.format.TextStyle.FULL, 
java.util.Locale.getDefault()) Collections.shuffle weather out.println 
"- " + dayName + ": " + weather.first() } %> """.stripIndent() def engine = new StreamingTemplateEngine() def template = 
engine.createTemplate(text) println template.make()

But if if want to define a function to simplify the code e.g.

def text = """\ <% def now = java.time.LocalDate.now() def 
dayName(java.time.LocalDate theDate) { return 
theDate.getDayOfWeek().getDisplayName(java.time.format.TextStyle.FULL, 
java.util.Locale.getDefault()) } %> # Hello Today (<%= dayName(now) %>) 
is <%= now %>. The weather in next 3 days will be: <% def weather = [ 
"Sunny", "Rainy", "Cloudy", "Windy" ] for (i = 1; i < 4; i++) { def day 
= now.plusDays(i) Collections.shuffle weather out.println "- " + 
dayName(day) + ": " + weather.first() } %> """.stripIndent() def engine = new StreamingTemplateEngine() def template = 
engine.createTemplate(text) println template.make()

...the StreamingTemplateEngine does not accept the function definition:


Template parse error 'Unexpected input: '(' ' at line 4, column 12
          3:
      --> 4: def dayName(java.time.LocalDate theDate) {
          5:     return 
theDate.getDayOfWeek().getDisplayName(java.time.format.TextStyle.FULL, 
java.util.Locale.getDefault())

groovy.text.TemplateParseException: Template parse error 'Unexpected 
input: '(' ' at line 4, column 12
          3:
      --> 4: def dayName(java.time.LocalDate theDate) {
          5:     return 
theDate.getDayOfWeek().getDisplayName(java.time.format.TextStyle.FULL, 
java.util.Locale.getDefault())


If there a way to define function in the text processed that would work 
with the StreamingTemplateEngine?


The code works fine "the other way around" i.e from Groovy code:

def now = java.time.LocalDate.now()

def dayName(java.time.LocalDate theDate) {
     return 
theDate.getDayOfWeek().getDisplayName(java.time.format.TextStyle.FULL, 
java.util.Locale.getDefault())
}

println "# Hello"

println "Today ${dayName(now)}) is ${now}."

println "The weather in next 3 days will be:"

def weather = [ "Sunny", "Rainy", "Cloudy", "Windy" ]
for (i = 1; i < 4; i++) {
   def day = now.plusDays(i)
   Collections.shuffle weather
   println "- " + dayName(day) + ": " + weather.first()
}

But I would like a "Markdown first" kind of experience rather than a 
"Groovy first" since in the "normal" case, the amount of text vastly 
outnumbers the amount of code.


Best regards,

Per