feat(src/StringConsumer): Add higher order consumers, integer, binary operation and if keywords consumers HEAD main

Higher order consumers are called that way because they use other (base)
consumers in their logic. In a sense, the other consumers are parameters
to the higher order consumers.

1 files changed, 27 insertions, 4 deletions

diff --git a/src/StringConsumer/IWordsConsumer.cl b/src/StringConsumer/IWordsConsumer.cl
index 4c184bf..a1c22ba 100644
--- a/src/StringConsumer/IWordsConsumer.cl
+++ b/src/StringConsumer/IWordsConsumer.cl
@@ -37,16 +37,37 @@ class WordList inherits System {
 
 	any_starts(s: String, start: Int) : Int {
 		if or(word = "", s.length() <= start)
-		then 0
+		then
+			0
+		else if and(s.length() < start + word.length(), not isvoid next)
+		then
+			next.any_starts(s, start)
 		else if s.substr(start, word.length()) = word
-		then word.length()
+		then
+			word.length()
 		else if isvoid next
-		then 0
-		else next.any_starts(s, start)
+		then
+			0
+		else
+			next.any_starts(s, start)
+		fi
 		fi
 		fi
 		fi
 	};
+
+	empty() : Bool {
+		if not (word = "")
+		then
+			false
+		else if isvoid next
+		then
+			true
+		else
+			next.empty()
+		fi
+		fi
+	};
 };
 
 class IWordsConsumer inherits IStringConsumer {
@@ -56,6 +77,8 @@ class IWordsConsumer inherits IStringConsumer {
 	let
 		word_length: Int <- 0
 	in {
+		assert(not matched_words.empty(), "consume", "object of class hasn't been initialised!");
+
 		consumed_length <- 0;
 		while 0 < (word_length <- matched_words.any_starts(s, consumed_length))
 		loop