There's a wide body of laws I've skimmed through -- such as Indian penal code, code of criminal procedure and Indian evidence act -- but none seem to have any provisions relating to rules of interpretation used by courts. The case law on this appears to be mostly persuasive rather than binding. Does this mean it's not a settled position about how laws are ought to be interpreted in India?
Some interpretive statutes are found in the national General Clauses Act (1897) and parallel state acts. Most of the rest is found in case law.
does this mean it's not a settled position about how laws are ought to be interpreted in India?
This question is not answered at the level of generality of "how laws ought to be interpreted in India". I wouldn't even know what an answer to that question would look like.
There are many guiding principles of interpretation, the starting place of which is to attempt to implement the intent of the legislature (something known as the "Golden Rule" of statutory interpretation in English common law) as expressed in the language of the statute to the extent that no other stronger interpretive principles apply.
But, basically, it is a problem to be worked out on a case by case basis in cases addressing alleged ambiguities in the meaning of a particular part of a particular statue. Most of the time, there is no ambiguity and so it isn't even recognized as an issue. What is ambiguous is frequently impossible to tell on the face of a statute until you are presented with facts in a case that create a context in which the meaning of a particular phrase or word or grammatical construction is unclear.
Statutory interpretation is a bottom up process in a legal system like India's, not a top down process. Questions arise one case at a time and bubble to the top, the issues aren't foreseen and resolved in advance.
Some of the other canons of interpretation which are buried in case law are to construe statutes in a way that makes them constitutional, to assume that there is not an intent to displace common law rules unless the text or comprehensive nature of a statute suggests otherwise, to give meaning of every part of the statute, to avoid absurd interpretations, and to consider legislative history when the proper interpretation is unclear.
Ultimately, statutory interpretation is not a mechanical problem like the order of operations in a mathematics equation. It requires a judge to employ good judgment and common sense to reach an interpretation that makes sense in the relevant context.