Add missing puctuation

[users/jgh/exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 837af5afc14fd16f3f190a12466e2c5e84d49974..ffe153ae9aedf91582b6f628d829b733c5bfefea 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -7346,22 +7346,25 @@ Apart from the escaping, the string within quotes takes the same form as the
 output when a single attribute is requested. Specifying no attributes is the
 same as specifying all of an entry's attributes.
 
+.new
 Here are some examples of the output format. The first line of each pair is an
 LDAP query, and the second is the data that is returned. The attribute called
-&%attr1%& has two values, whereas &%attr2%& has only one value:
+&%attr1%& has two values, one of them with an embedded comma, whereas
+&%attr2%& has only one value:
 .code
 ldap:///o=base?attr1?sub?(uid=fred)
-value1.1,value1.2
+value1.1,value1,,2
 
 ldap:///o=base?attr2?sub?(uid=fred)
 value two
 
 ldap:///o=base?attr1,attr2?sub?(uid=fred)
-attr1="value1.1,value1.2" attr2="value two"
+attr1="value1.1,value1,,2" attr2="value two"
 
 ldap:///o=base??sub?(uid=fred)
-objectClass="top" attr1="value1.1,value1.2" attr2="value two"
+objectClass="top" attr1="value1.1,value1,,2" attr2="value two"
 .endd
+.wen
 You can
 make use of Exim's &%-be%& option to run expansion tests and thereby check the
 results of LDAP lookups.
@@ -7370,6 +7373,8 @@ individual fields from data that consists of &'key'&=&'value'& pairs.
 .new
 The &%listextract%& operator should be used to pick out individual values
 of attributes, even when only a single value is expected.
+The doubling of embedded commas allows you to use the returned data as a
+comma separated list (using the "<," syntax for changing the input list separator).
 .wen
 
 
@@ -16822,6 +16827,39 @@ If the expansion fails (other than forced failure) delivery is deferred. Some
 of the other precondition options are common special cases that could in fact
 be specified using &%condition%&.
 
+.new
+When originally designed, Exim's ACL system enforced very strict parsing
+of the &%condition%& expansion everywhere it was being processed.
+Through the 4.7x release cycle, the &%condition%& processing while in a
+router became more loose, internally adopting the use of &%bool_lax%&
+instead of the more rigid &%bool%&.  This is best illustrated in an
+example:
+.code
+# This used to fail with a syntax error, now it
+# treats any extra characters as a string
+
+$ exim -be '${if eq {${lc:GOOGLE.com}} {google.com}} {yes} {no}}'
+true {yes} {no}}
+
+$ exim -be '${if eq {${lc:WHOIS.com}} {google.com}} {yes} {no}}'
+ {yes} {no}}
+.endd
+In each example above, the &%if%& statement actually ends after
+&"{google.com}}"&.  Since no true or false braces were defined, the
+default &%if%& behavior is to return a boolean true or a null answer
+(which evaluates to false). The rest of the line is then treated as a
+string. So the first example resulted in the boolean answer &"true"&
+with the string &" {yes} {no}}"& appended to it. The second example
+resulted in the null output (indicating false) with the string
+&" {yes} {no}}"& appended to it.
+
+In fact you can put excess forward braces in too.  In the router
+&%condition%&, Exim's ACL parser only looks for &"{"& symbols when they
+mean something, like after a &"$"& or when required as part of a
+conditional.  But otherwise &"{"& and &"}"& are treated as ordinary
+string characters.
+.wen
+
 
 .option debug_print routers string&!! unset
 .cindex "testing" "variables in drivers"