cairo: Fix crashes and bugs in 'setup' call.

[pspp] / doc / dev / system-file-format.texi

diff --git a/doc/dev/system-file-format.texi b/doc/dev/system-file-format.texi
index 4f5aa7edbeb749f39ba0f4b4af000f61a307afdc..b8670681d9e3789a9803d1e31eae56d54ac32cc7 100644 (file)
--- a/doc/dev/system-file-format.texi
+++ b/doc/dev/system-file-format.texi
@@ -9,11 +9,14 @@
 @c
 
 @node System File Format
-@appendix System File Format
+@chapter System File Format
 
-A system file encapsulates a set of cases and dictionary information
-that describes how they may be interpreted.  This chapter describes
-the format of a system file.
+An SPSS system file holds a set of cases and dictionary information
+that describes how they may be interpreted.  The system file format
+dates back 40+ years and has evolved greatly over that time to support
+new features, but in a way to facilitate interchange between even the
+oldest and newest versions of software.  This chapter describes the
+system file format.
 
 System files use four data types: 8-bit characters, 32-bit integers,
 64-bit integers,
@@ -1001,18 +1004,24 @@ members are as follows:
 
 @table @code
 @item int32 measure;
-The measurement type of the variable:
+The measurement level of the variable:
 @table @asis
+@item 0
+Unknown
 @item 1
-Nominal Scale
+Nominal
 @item 2
-Ordinal Scale
+Ordinal
 @item 3
-Continuous Scale
+Scale
 @end table
 
-SPSS sometimes writes a @code{measure} of 0.  PSPP interprets this as
-nominal scale.
+An ``unknown'' @code{measure} of 0 means that the variable was created
+in some way that doesn't make the measurement level clear, e.g.@: with
+a @code{COMPUTE} transformation.  PSPP sets the measurement level the
+first time it reads the data using the rules documented in
+@ref{Measurement Level,,,pspp, PSPP Users Guide}, so this should
+rarely appear.
 
 @item int32 width;
 The width of the display column for the variable in characters.
@@ -1518,7 +1527,8 @@ the following believed meanings:
 
 @table @asis
 @item 5
-A set of grouped variables (according to Aapi H@"am@"al@"ainen).
+A named variable set for use in the GUI (according to Aapi
+H@"am@"al@"ainen).
 
 @item 6
 Date info, probably related to USE (according to Aapi H@"am@"al@"ainen).