Add isStreamCompleted function

src_v2/parser/parser_internals.nim

@@ -32,6 +32,15 @@ proc lookBack*(count: int): (parserFnT) =
       tokens: parser.tokens,
     ).ok()
 
+proc isStreamCompleted*(parser: Parser): bool =
+  parser.state.position >= parser.state.stream.len - 1
+
+proc isStreamCompleted*(parserResult: ParserResult): bool =
+  parserResult.fold(
+    err => false,
+    isStreamCompleted,
+  )
+
 # -- Parsing Proctions
 
 proc ch*(expectedChars: set[char]): parserFnT {.inline.} =
@@ -248,10 +257,9 @@ when isMainModule:
 
   block testBlockChar:
     let ch1 = ch('1')
-    let ch2 = ch('2')
-    let ch3 = ch('3')
     let chDigits = ch(Digits)
 
+    # Success
     assert testParser123.flatMap(ch1).tokensToString() == "1"
     assert testParser123.flatMap(anyCh).tokensToString() == "1"
     assert testParser123.flatMap(chDigits).tokensToString() == "1"
@@ -263,3 +271,8 @@ when isMainModule:
     # Out of bounds
     assert initParserResult("").flatMap(ch1).error().kind == endOfStringErr
     assert initParserResult("1").flatMap(ch1).flatMap(ch1).error().kind == endOfStringErr
+
+    # Stream end reached
+    assert initParserResult("1").flatMap(ch1).isStreamCompleted() == true
+    assert initParserResult("12").flatMap(ch1).isStreamCompleted() == false
+    assert initParserResult("").flatMap(ch1).isStreamCompleted() == false