forked from GitHub/gf-core
document the four new language features in the reference manual
This commit is contained in:
kr.angelov
@@ -5,7 +5,7 @@
|
||||
</HEAD><BODY BGCOLOR="white" TEXT="black">
|
||||
<P ALIGN="center"><CENTER><H1>GF Language Reference Manual</H1>
|
||||
<FONT SIZE="4">
|
||||
<I>Aarne Ranta</I><BR>February 2008
|
||||
<I>Aarne Ranta</I>, <I>Krasimir Angelov</I><BR>November 2013
|
||||
</FONT></CENTER>
|
||||
|
||||
<P></P>
|
||||
@@ -39,6 +39,7 @@
|
||||
<LI><A HREF="#toc22">Linearization type definitions, lincat</A>
|
||||
<LI><A HREF="#toc23">Linearization definitions, lin</A>
|
||||
<LI><A HREF="#toc24">Linearization default definitions, lindef</A>
|
||||
<LI><A HREF="#toc24_r">Linearization reference definitions, linref</A>
|
||||
<LI><A HREF="#toc25">Printname definitions, printname cat and printname fun</A>
|
||||
<LI><A HREF="#toc26">Parameter type definitions, param</A>
|
||||
<LI><A HREF="#toc27">Parameter values</A>
|
||||
@@ -968,8 +969,15 @@ name to the scope.
|
||||
<TD>yes</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>lindef</CODE> f = t</TD>
|
||||
<TD>f fun, t term</TD>
|
||||
<TD><CODE>lindef</CODE> C = t</TD>
|
||||
<TD>C cat, t term</TD>
|
||||
<TD>concrete*</TD>
|
||||
<TD>yes</TD>
|
||||
<TD>no</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>linref</CODE> C = t</TD>
|
||||
<TD>C cat, t term</TD>
|
||||
<TD>concrete*</TD>
|
||||
<TD>yes</TD>
|
||||
<TD>no</TD>
|
||||
@@ -1355,11 +1363,17 @@ type of <I>C</I>.
|
||||
Linearization defaults are invoked when linearizing variable bindings
|
||||
in higher-order abstract syntax. A variable symbol is then presented
|
||||
as a string, which must be converted to correct type in order for
|
||||
linearization not to fail with an error.
|
||||
the linearization not to fail with an error.
|
||||
</P>
|
||||
<P>
|
||||
The defaults can also be used for linearizing metavariables
|
||||
in an interactive syntax editor.
|
||||
The other use of the defaults is for linearizing metavariables
|
||||
and abstract functions without linearization in the concrete syntax.
|
||||
In the first case the default linearization is applied to
|
||||
the string <CODE>"?X"</CODE> where <CODE>X</CODE> is the unique index
|
||||
of the metavariable, and in the second case the string is
|
||||
<CODE>"[f]"</CODE> where <CODE>f</CODE> is the name of the abstract
|
||||
function with missing linearization.
|
||||
|
||||
</P>
|
||||
<P>
|
||||
Usually, linearization defaults are generated by using the default
|
||||
@@ -1376,8 +1390,62 @@ definition is by structural recursion on the type:
|
||||
|
||||
<P>
|
||||
The notion of the first value of a parameter type (#1(P)) is defined
|
||||
<a href="#paramvalues">here</a> below.
|
||||
<a href="#paramvalues">below</a>.
|
||||
</P>
|
||||
<A NAME="toc24_r"></A>
|
||||
<H3>Linearization reference definitions, linref</H3>
|
||||
<P>
|
||||
<a name="linrefjudgements"></a>
|
||||
</P>
|
||||
<P>
|
||||
A linearization reference definition,
|
||||
<center>
|
||||
<CODE>linref</CODE> <I>C</I> <CODE>=</CODE> <I>t</I>
|
||||
</center>
|
||||
defines the reference linearization of category <I>C</I>, i.e. the function
|
||||
applicable to an object of the linearization type of <I>C</I> to make it into a string.
|
||||
</P>
|
||||
<P>
|
||||
The reference linearization is always applied to the top-level node
|
||||
of the abstract syntax tree. For example when we linearize the
|
||||
tree <CODE>f x1 x2 .. xn</CODE>, then we first apply <CODE>f</CODE>
|
||||
to its arguments which gives us an object of the linearization type of
|
||||
its category. After that we apply the reference linearization
|
||||
for the same category to get a string out of the object. This
|
||||
is particularly useful when the linearization type of <I>C</I>
|
||||
contains discontious constituents. In this case usually the reference
|
||||
linearization glues the constituents together to produce an
|
||||
intuitive linearization string.
|
||||
</P>
|
||||
<P>
|
||||
The reference linearization is also used for linearizing metavariables
|
||||
which stand in function position. For example the tree
|
||||
<CODE>f (? x1 x2 .. xn)</CODE> is linearized as follows. Each
|
||||
of the arguments <CODE>x1 x2 .. xn</CODE> is linearized, and after that
|
||||
the reference linearization of the its category is applied
|
||||
to the output of the linearization. The result is a sequence of <CODE>n</CODE>
|
||||
strings which are concatenated into a single string. The final string
|
||||
is the input to the default linearization of the category
|
||||
for the argument of <CODE>f</CODE>. After applying the default linearization
|
||||
we get an object that we could safely pass to <CODE>f</CODE>.
|
||||
</P>
|
||||
<P>
|
||||
Usually, linearization references are generated by using the
|
||||
rule that "picks the first string in the linearization type". The precise
|
||||
definition is by structural recursion on the type:
|
||||
</P>
|
||||
<UL>
|
||||
<LI>reference(Str,o) = Just o
|
||||
<LI>reference(P,s) = Nothing
|
||||
<LI>reference(P => T,o) = reference(T,o ! #1(P)) || reference(T,o ! #2(P)) || ... || reference(T,o ! #n(P))
|
||||
<LI>reference({r1 : R1; ... rn : Rn},o) = reference(R1, o.r1) || reference(R2, o.r2) || ... || reference(Rn, o.rn)
|
||||
</UL>
|
||||
Here each call to reference returns either <CODE>(Just o)</CODE> or <CODE>Nothing</CODE>.
|
||||
When we compute the reference for a table or a record then we pick
|
||||
the reference for the first expression for which the recursive call
|
||||
gives us <CODE>Just</CODE>. If we get <CODE>Nothing</CODE> for
|
||||
all of them then the final result is <CODE>Nothing</CODE> too.
|
||||
|
||||
<A NAME="toc25"></A>
|
||||
<H3>Printname definitions, printname cat and printname fun</H3>
|
||||
<P>
|
||||
@@ -2927,7 +2995,7 @@ literals).
|
||||
<H3>Predefined concrete syntax operations</H3>
|
||||
<P>
|
||||
The following predefined operations are defined in the resource module
|
||||
<CODE>prelude/Predefined.gf</CODE>. Their implementations are defined as
|
||||
<CODE>prelude/Predef.gf</CODE>. Their implementations are defined as
|
||||
a part of the GF grammar compiler.
|
||||
</P>
|
||||
<TABLE ALIGN="center" CELLPADDING="4" BORDER="1">
|
||||
@@ -3031,6 +3099,26 @@ a part of the GF grammar compiler.
|
||||
<TD><CODE>(L : Type) -> L -> Str</CODE></TD>
|
||||
<TD>find the "first" string</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>nonExist</CODE></TD>
|
||||
<TD><CODE>Str</CODE></TD>
|
||||
<TD>this is a special token marking<BR/>
|
||||
non-existing morphological forms</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>BIND</CODE></TD>
|
||||
<TD><CODE>Str</CODE></TD>
|
||||
<TD>this is a special token marking<BR/>
|
||||
that the surrounding tokens should not<BR/>
|
||||
be separated by space</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>SOFT_BIND</CODE></TD>
|
||||
<TD><CODE>Str</CODE></TD>
|
||||
<TD>this is a special token marking<BR/>
|
||||
that the surrounding tokens may not<BR/>
|
||||
be separated by space</TD>
|
||||
</TR>
|
||||
</TABLE>
|
||||
|
||||
<P></P>
|
||||
@@ -3427,24 +3515,25 @@ The reserved words used in GF are the following:
|
||||
<TD><CODE>lindef</CODE></TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>linref</CODE></TD>
|
||||
<TD><CODE>of</CODE></TD>
|
||||
<TD><CODE>open</CODE></TD>
|
||||
<TD><CODE>oper</CODE></TD>
|
||||
<TD><CODE>param</CODE></TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>param</CODE></TD>
|
||||
<TD><CODE>pre</CODE></TD>
|
||||
<TD><CODE>printname</CODE></TD>
|
||||
<TD><CODE>resource</CODE></TD>
|
||||
<TD><CODE>strs</CODE></TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>strs</CODE></TD>
|
||||
<TD><CODE>table</CODE></TD>
|
||||
<TD><CODE>transfer</CODE></TD>
|
||||
<TD><CODE>variants</CODE></TD>
|
||||
<TD><CODE>where</CODE></TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD><CODE>where</CODE></TD>
|
||||
<TD><CODE>with</CODE></TD>
|
||||
<TD></TD>
|
||||
<TD></TD>
|
||||
@@ -3773,6 +3862,11 @@ All other symbols are terminals.
|
||||
<TR>
|
||||
<TD></TD>
|
||||
<TD ALIGN="center"><B>|</B></TD>
|
||||
<TD><CODE>linref</CODE> <I>[Def]</I></TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD></TD>
|
||||
<TD ALIGN="center"><B>|</B></TD>
|
||||
<TD><CODE>lin</CODE> <I>[Def]</I></TD>
|
||||
</TR>
|
||||
<TR>
|
||||
|
||||
Reference in New Issue
Block a user