make unary minus part of number literals, refs #17020 (#17488)

* make unary minus part of number literals, refs #17020
* fixes regression

tests/lexer/tunary_minus.nim

@@ -0,0 +1,76 @@
+discard """
+  targets: "c cpp js"
+"""
+
+# Test numeric literals and handling of minus symbol
+
+import std/[macros, strutils]
+
+macro lispReprStr*(a: untyped): untyped = newLit(a.lispRepr)
+
+macro assertAST*(expected: string, struct: untyped): untyped =
+  var ast = newLit(struct.treeRepr)
+  result = quote do:
+    if `ast` != `expected`:
+      doAssert false, "\nGot:\n" & `ast`.indent(2) & "\nExpected:\n" & `expected`.indent(2)
+
+const one = 1
+const minusOne = `-`(one)
+
+# border cases that *should* generate compiler errors:
+assertAST dedent """
+  StmtList
+    Asgn
+      Ident "x"
+      Command
+        IntLit 4
+        IntLit -1""":
+  x = 4 -1
+assertAST dedent """
+  StmtList
+    VarSection
+      IdentDefs
+        Ident "x"
+        Ident "uint"
+        IntLit -1""":
+  var x: uint = -1
+template bad() =
+  x = 4 -1
+doAssert not compiles(bad())
+
+template main =
+  block: # check when a minus (-) is a negative sign for a literal
+    doAssert -1 == minusOne:
+      "unable to parse a spaced-prefixed negative int"
+    doAssert lispReprStr(-1) == """(IntLit -1)"""
+    doAssert -1.0'f64 == minusOne.float64
+    doAssert lispReprStr(-1.000'f64) == """(Float64Lit -1.0)"""
+    doAssert lispReprStr( -1.000'f64) == """(Float64Lit -1.0)"""
+    doAssert [-1].contains(minusOne):
+      "unable to handle negatives after square bracket"
+    doAssert lispReprStr([-1]) == """(Bracket (IntLit -1))"""
+    doAssert (-1, 2)[0] == minusOne:
+      "unable to handle negatives after parenthesis"
+    doAssert lispReprStr((-1, 2)) == """(Par (IntLit -1) (IntLit 2))"""
+    proc x(): int =
+      var a = 1;-1  # the -1 should act as the return value
+    doAssert x() == minusOne:
+      "unable to handle negatives after semi-colon"
+
+  block: # check when a minus (-) is an unary op
+    doAssert -one == minusOne:
+      "unable to a negative prior to identifier"
+
+  block: # check when a minus (-) is a a subtraction op
+    doAssert 4-1 == 3:
+      "unable to handle subtraction sans surrounding spaces with a numeric literal"
+    doAssert 4-one == 3:
+      "unable to handle subtraction sans surrounding spaces with an identifier"
+    doAssert 4 - 1 == 3:
+      "unable to handle subtraction with surrounding spaces with a numeric literal"
+    doAssert 4 - one == 3:
+      "unable to handle subtraction with surrounding spaces with an identifier"
+
+
+static: main()
+main()