Improved AST parser

src/build/ast/parseNode.go

@@ -0,0 +1,42 @@
+package ast
+
+import (
+	"git.akyoto.dev/cli/q/src/build/errors"
+	"git.akyoto.dev/cli/q/src/build/expression"
+	"git.akyoto.dev/cli/q/src/build/token"
+)
+
+// parseNode generates an AST node from an instruction.
+func parseNode(tokens token.List, source []byte) (Node, error) {
+	if tokens[0].IsKeyword() {
+		return parseKeyword(tokens, source)
+	}
+
+	expr := expression.Parse(tokens)
+
+	if expr == nil {
+		return nil, nil
+	}
+
+	switch {
+	case IsVariableDefinition(expr):
+		if len(expr.Children) < 2 {
+			return nil, errors.New(errors.MissingOperand, nil, expr.Token.End())
+		}
+
+		return &Define{Expression: expr}, nil
+
+	case IsAssignment(expr):
+		if len(expr.Children) < 2 {
+			return nil, errors.New(errors.MissingOperand, nil, expr.Token.End())
+		}
+
+		return &Assign{Expression: expr}, nil
+
+	case IsFunctionCall(expr):
+		return &Call{Expression: expr}, nil
+
+	default:
+		return nil, errors.New(&errors.InvalidInstruction{Instruction: expr.Token.Text(source)}, nil, expr.Token.Position)
+	}
+}