Construct a script engine (5) that uses a C language to check the syntax, generate a syntax tree, and generate code.

Construct a script engine using C language (5)

Author: kevin_qing

Please note

Syntax check, constant merging and the new idiom method tree are implemented in reduce normalization functions.

Syntax tree node Definition

Struct gtreenode {

Uint32_t type;

Uint32_t value;

};

Struct gtreenode1: Public gtreenode {

Gtreenode * Child1;

};

Struct gtreenode2: Public gtreenode1 {

Gtreenode * child2;

};

Struct gtreenode3: Public gtreenode2 {

Gtreenode * Child3;

};

Struct gtreenoden: Public gtreenode {

Array <gtreenode> Childs;

};

Type indicates the node type, such as if switch op_2 op_1 smt_seq (statement sequence) cpd_smt (composite statement) Case VAR numbers.

Value is a value of the corresponding type, such as the case label, string ID, constant value, and op_2 operation.

Gtreenode1 corresponds to the 1 RMB operation, such as not

Gtreenode2 corresponds to 2 meta operations, such as IF-SMT, +-*/% and other arithmetic logic operations

Gtreenode2 corresponds to a 3 yuan operation, typically a IF-SMT-ELSE-SMT

Sequence of gtreenoden statements

The syntax tree is generated inside the Statute function, and sub-nodes are added through stacks. Similar to token.

When a syntax tree node is generated, you can perform a semantic check and check whether the operands are constants. Instead, you can perform a constant merge optimization code.

When generating code, traverse the syntax tree in sequence. It is mainly because lable requires backtracking, and there are no other difficulties.

To be continued