Debug
context, print, println — what’s actually in scope here?
When a template isn’t rendering what you thought it would, these builtins help you peek inside without leaving the template.
| Function | Arity | Signature | What |
|---|---|---|---|
context | 0 | context | Print the entire current data context to stdout |
print | 0+ | print v ... | Print one or more values to stdout, comma-separated, no trailing newline |
println | 0+ | println v ... | Same as print but with a trailing newline |
All three are side-effect-only: their return value is unit / null,
so you generally call them as statements inside a template rather
than interpolating their result. The output goes to the Scala
process’s stdout, not to the template’s render buffer.
context — dump the whole scope
{{ context }}…dumps everything the template can see at this point — the current
data, plus locals introduced by enclosing with / for / :=
blocks. Useful when a field reference unexpectedly renders empty:
drop a {{ context }} above it and check whether the field is
actually there.
print / println — log a specific value
{{ println 'rendering page:' .page.title }}
{{ print 'tag count =' (length .page.tags) }}When you need more
For non-trivial debugging it’s often easier to instrument from
Scala — write a small inspect: Any => Any template function that
printlns its argument and returns it unchanged, then drop
{{ inspect .x }} wherever you want a peek without breaking the
flow. Squiggly’s data-context model means everything in scope is just
a Scala value; you have full freedom to instrument it from outside
the template.
Other useful checks
fileExists path—trueiff a file on disk is readable. Lives in URL & text helpers but often comes up during debugging when a template lookup fails.toString v— coerce any value to itsStringform. Handy when you want to confirm what a non-string value will look like when interpolated.