add some stuff about string literals to the readme

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Change-Id: I7bda5d1ad0c6b1b44ea283b429b14fd397ef978a

1 files changed, 27 insertions, 0 deletions

diff --git a/README.txt b/README.txt
index 334f3b8..a6690e4 100644
--- a/README.txt
+++ b/README.txt
@@ -70,6 +70,33 @@ versions as you modify Evocation.
 
   Some helpful words to try to get started are list-dictionary and describe.
 
+  The syntax for a string literal is s" ...". There's something very subtle
+happening: it's the lowercase letter "s", a double quote, and a space. Then
+you type the actual contents of the string, then at the end you type another
+double quote. The words "Hi, Irenes!", in the example above, are part of a
+closely related syntax that uses a period instead of a letter s, and prints
+the string out to your terminal instead of returning it.
+
+  Whether you're using s" or .", that space after the quote is mandatory,
+which may seem very strange if you're more familiar with pretty much any
+language that isn't a Forth, but it's a common Forth idiom. Requiring the
+space allows the string literal syntax to be tokenized just like any other
+space-delimited word. Unlike most languages, there's no special concept of an
+operator or punctuation character that can "interrupt" another word or run up
+against the start of one. Everything is separated by spaces.
+
+  Of course, in modern Forth dialects it's also very common to add a special
+lexer feature for that sort of thing. Evocation doesn't do that, because
+eventually fancy syntax and grammar will be implemented at a higher layer,
+using the experimental parsing formalism that doesn't exist yet. If you want
+to see where this feature would be if it were implemented in the simpler way,
+you can read the definition of the word named "word", in interpret.e.
+
+  If you went to look at that and you're wondering: Yeah, Evocation's lexer
+really is that short and simple. Part of why it's able to be that easy is that
+words such as s" that introduce special syntaxes do their own lexing for
+whatever comes after them.
+
 
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ~~ Reading Evocation's source code ~~