development grammar: remove string interpolation options & add sep …

…function (#381)

per openwdl/wdl#229

WDL/StdLib.py

@@ -77,6 +77,10 @@ def sub(input: Value.String, pattern: Value.String, replace: Value.String) -> Va
  def defined(v: Value.Base):
  return Value.Boolean(not isinstance(v, Value.Null))
 
+ @static([Type.String(), Type.Array(Type.String())], Type.String())
+ def sep(sep: Value.String, iterable: Value.Array) -> Value.String:
+ return Value.String(sep.value.join(v.value for v in iterable.value))
+
  # write_*
  static([Type.Array(Type.String())], Type.File(), "write_lines")(
  self._write(_serialize_lines)

WDL/_grammar.py

@@ -321,12 +321,7 @@
 output_decls: "output" "{" bound_decl* "}"
 
 // WDL task commands: with {} and <<< >>> command and ${} and ~{} placeholder styles
-!?placeholder_key: "default" | "false" | "true" | "sep"
-?placeholder_value: string_literal
- | INT -> int
- | FLOAT -> float
-placeholder_option: placeholder_key "=" placeholder_value
-placeholder: placeholder_option* expr
+placeholder: expr
 
 ?command: command1 | command2
 

tests/test_5stdlib.py

@@ -713,6 +713,50 @@ def test_zip_cross(self):
  }
  """, expected_exception=WDL.Error.EvalError)
 
+ def test_sep(self):
+ outputs = self._test_task(R"""
+ version development
+ task SepTest {
+ input {
+ Array[String] inp = ["value1", "value2", "value3"]
+ }
+ command {}
+ output {
+ String out = sep(",", inp)
+ }
+ }
+ """)
+ self.assertEqual("value1,value2,value3", outputs["out"])
+
+ outputs = self._test_task(R"""
+ version development
+ task SepTest {
+ input {
+ Array[String] inp = ["value1", "value2", "value3"]
+ }
+ command <<<
+ echo ~{sep(",", inp)}
+ >>>
+
+ output {
+ String out = read_string(stdout())
+ }
+ }
+ """)
+ self.assertEqual("value1,value2,value3", outputs["out"])
+
+ self._test_task(R"""
+ version development
+ task SepTest {
+ input {
+ Array[String] inp = ["value1", "value2", "value3"]
+ }
+ command <<<
+ echo ~{sep="," inp}
+ >>>
+ }
+ """, expected_exception=WDL.Error.SyntaxError)
+
 
  def test_suffix(self):
  outputs = self._test_task(R"""