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* Refactoring: combine functions that take an attribute set and

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functions that take a single argument (plain lambdas) into one AST
  node (Function) that contains a Pattern node describing the
  arguments.  Current patterns are single lazy arguments (VarPat) and
  matching against an attribute set (AttrsPat).

  This refactoring allows other kinds of patterns to be added easily,
  such as Haskell-style @-patterns, or list pattern matching.
This commit is contained in:
Eelco Dolstra 2008-08-14 10:04:22 +00:00
parent c03b729319
commit efe4b690ae
12 changed files with 184 additions and 148 deletions
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33
src/libexpr/parser.y
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@ -237,9 +237,9 @@ expr: expr_function;
expr_function
: '{' formals '}' ':' expr_function
{ $$ = makeFunction($2, $5, CUR_POS); }
{ $$ = makeFunction(makeAttrsPat($2), $5, CUR_POS); }
| ID ':' expr_function
{ $$ = makeFunction1($1, $3, CUR_POS); }
{ $$ = makeFunction(makeVarPat($1), $3, CUR_POS); }
| ASSERT expr ';' expr_function
{ $$ = makeAssert($2, $4, CUR_POS); }
| WITH expr ';' expr_function
@ -387,22 +387,37 @@ static void checkAttrs(ATermMap & names, ATermList bnds)
}
static void checkAttrSets(ATerm e)
static void checkPatternVars(ATerm pos, ATermMap & map, Pattern pat)
{
ATerm name;
ATermList formals;
ATerm body, pos;
if (matchFunction(e, formals, body, pos)) {
ATermMap names(ATgetLength(formals));
if (matchVarPat(pat, name)) {
if (map.get(name))
throw EvalError(format("duplicate formal function argument `%1%' at %2%")
% aterm2String(name) % showPos(pos));
map.set(name, name);
}
else if (matchAttrsPat(pat, formals)) {
for (ATermIterator i(formals); i; ++i) {
ATerm name;
ATerm d1;
if (!matchFormal(*i, name, d1)) abort();
if (names.get(name))
if (map.get(name))
throw EvalError(format("duplicate formal function argument `%1%' at %2%")
% aterm2String(name) % showPos(pos));
names.set(name, name);
map.set(name, name);
}
}
else abort();
}
static void checkAttrSets(ATerm e)
{
ATerm pat, body, pos;
if (matchFunction(e, pat, body, pos)) {
ATermMap map(16);
checkPatternVars(pos, map, pat);
}
ATermList bnds;
if (matchAttrs(e, bnds)) {