add mathematical solver engine based on sympy

math_lexer.py

@@ -0,0 +1,61 @@
+
+
+
+EXPRESSION = 0
+END_OF_INPUT = 1
+
+SOLVE = "solve"
+FOR = "for"
+AND = "and"
+EQUALS = "="
+COMMA = ","
+
+keyword_tokens = [SOLVE, FOR, AND, EQUALS, COMMA]
+
+
+
+class Token:
+    def __init__(self, type: int|str, value: str = None):
+        self.type = type
+        self.value = value
+
+    def __repr__(self):
+        if self.value == None:
+            return f"{self.type}"
+        return f"{self.type}|'{self.value}'"
+
+
+def tokenize(expression: str) -> list[Token]:
+    """
+    this splits a math instruction into tokens.
+    example:
+        "solve x + 1 = 5 and y = 2*x for x, y"
+    result:
+        ["solve", "x + 1", "=", "5", "and", "y", "=", "2*x", "for", "x", "and", "y", "end_of_input"]
+    """
+
+    tokens = []   # output list of tokens
+
+    symbols = expression.replace(",", " , ").replace("=", " = ").split(" ")
+
+    current_token = []  # everything that is not directly in math_keyword_tokens gets binned here
+    for s in symbols:
+        found = False
+
+        for keyword in keyword_tokens:
+            if s.lower() == keyword:
+                if len(current_token) != 0:
+                    tokens.append(Token(EXPRESSION, " ".join(current_token)))
+                    current_token = []
+                tokens.append(Token(keyword))
+                found = True
+                break
+
+        if found == False:
+            current_token.append(s)
+    if len(current_token) != 0:
+        tokens.append(Token(EXPRESSION, " ".join(current_token)))
+        current_token = []
+
+    tokens.append(Token(END_OF_INPUT))
+    return tokens