//<if> -> IF ( <expr> <RO> <expr>) THEN <block>
node_t* if_f() {
node_t *p = getNode("<if>");
if (tk.name == "(") { // (
//don't need to put delimiters in the tree
tk = scanner(fp, lineNum);
p->child1 = expr_f();
p->child2 = RO_f();
p->child3 = expr_f();
if (tk.name == ")") { // )
//don't need to put delimiters in the tree
tk = scanner(fp, lineNum);
if (tk.tokenId == THEN_tk) {
tk = scanner(fp, lineNum);
p->child4 = block_f();
return p;
} else {
error("Got token " + tk.name = ", expected THEN token\n'");
}
} else {
error("Got token " + tk.name = ", expected ) token\n");
}
} else {
error("Got token " + tk.name = ", expected ( token\n");
}
return p;
}
void partial_block_f()
{
if (state!=partial_block)
{
delete WGr_pointer; WGr_pointer=NULL;
delete block_pointer; // destroy installed block first
block_pointer =
new non_integral_block(currentRepContext(),
currentStandardRepr());
state=partial_block;
entry_z = current_param_block().size()-1;
}
block_f();
} // |partial_block_f|
void nblock_f()
{
if (state!=nblock)
{
delete WGr_pointer; WGr_pointer=NULL;
delete block_pointer; // destroy installed block first
block_pointer =
new non_integral_block(currentRepContext(),
currentStandardRepr(),
entry_z);
state=nblock;
}
block_f();
} // |nblock_f|
//<program> -> PROGRAM <var> <block>
node_t* prog_f() {
node_t *p = getNode("<program>");
if(tk.tokenId == PROG_tk) { // PROGRAM
p->child1 = getNode("PROGRAM");
tk = scanner(fp, lineNum);
p->child2 = var_f();
p->child3 = block_f();
return p;
} else {
error("Got token " + tk.name + ", expected PROGRAM token\n");
}
return p;
}
//<stat> -> <in> | <out> | <block> | <if> | <loop> | <assign>
node_t* stat_f() {
node_t *p = getNode("<stat>");
if (tk.tokenId == SCAN_tk) { // <in>
p->child1 = getNode("SCAN");
tk = scanner(fp, lineNum);
p->child2 = in_f();
return p;
} else if (tk.tokenId == PRINT_tk) { // <out>
p->child1 = getNode("PRINT");
tk = scanner(fp, lineNum);
p->child2 = out_f();
return p;
} else if (tk.name == "{") { // <block>
//don't need to put delimiters in the tree
p->child1 = block_f();
return p;
} else if (tk.tokenId == IF_tk) { // <if>
p->child1 = getNode("IF");
tk = scanner(fp, lineNum);
p->child2 = if_f();
return p;
} else if (tk.tokenId == LOOP_tk) { // <loop>
p->child1 = getNode("LOOP");
tk = scanner(fp, lineNum);
p->child2 = loop_f();
return p;
} else if (tk.tokenId == IDENT_tk) { // <assign>
p->child1 = assign_f();
return p;
} else {
error("Got token " + tk.name + ", expected SCAN, PRINT, {, IF, LOOP, or IDENTIFIER token\n");
}
return p;
}
