Examine an executing Power Query mashup under a microscope and what to you see? Data pulsing down pathways between expressions. Increase your microscope’s magnifying power. As you zoom in on one of the flows, what you’re viewing transforms from a blurred stream of data into the individual data items that make up that flow.
As you study what you see, you notice that the data items flowing by fit into groupings based on the kind of value they contain: some hold text, others are made up of a date, a time or a datetime; yet others are true/false values, then there are numbers…and it looks like there are even more categories beyond these!
In this post, we’ll begin exploring these categories—we’ll begin exploring the kinds of values supported by the M language. In programming parlance, these kinds of values” are called types.
Types can have special behaviors associated with them. For example, date and time have a special rule around addition: add a date and a time together and you get back a datetime! We’ll investigate these special rules.
Also, we’ll discuss the literal syntax associated with each type. In this context, ”literal” implies that you literally want to write out a value in code. You might, for example, literally want to set variable rate to the hand-selected value of 100. The syntax you use to code up the expression that produces the literal value you want is called literal syntax. Different types have different literal syntax rules. We’ll talk about these rules, as well.
There’s a lot to cover. In this post, we’ll explore the specifics of text (strings). If we explored all of the types in this post, it would get mighty long, so we’ll save the others for later.