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start parsing statements (not a lot yet)

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pommicket 2022-02-03 22:53:38 -05:00
parent fd02968c23
commit d1167f03d0
4 changed files with 260 additions and 65 deletions
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46
05/constants.b
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@ -230,6 +230,52 @@
; types willl be initialized (in main) so that this refers to the type char*
#define TYPE_POINTER_TO_CHAR 20
; STATEMENTS
; In C, note that `if', `while', etc. always have a single statement as their body:
; if (x) { y; z; w; }
; here {y; z; w;} is a single `compound' statement containing three statements.
; our statements don't directly correspond to the C89 standard's notion of statements, in particular,
; labels count as separate statements and declarations count as statements.
; each statement is stored as exactly 40 bytes
; uchar type
; uchar padding
; ushort file
; uint line
; ulong data1
; ulong data2
; ulong data3
; ulong data4
; a type of 0 indicates the end of the block.
; data layout for particular statements:
; - STATEMENT_EXPRESSION - data1 is a pointer to expression data; data2,3,4 are unused
; - STATEMENT_LOCAL_DECLARATION - declaring a local variable (automatic/"register" storage duration), data1 = total bytes used by all local variables so far in this function including this one; data2,3,4 unused
; - STATEMENT_LABEL - data1 is a pointer to the name of the label; data2,3,4 are unused
; - STATEMENT_BLOCK - data1 is a pointer to an array of statements; data2,3,4 are unused
; - STATEMENT_IF - data1 is a pointer to the condition, data2 is a pointer to the `if' branch statement, data3 is a pointer to the `else' branch statement, or 0 if there is none; data4 is unused
; - STATEMENT_SWITCH - data1 is a pointer to the expression, data2 is a pointer to the body statement; data3,4 are unused
; - STATEMENT_WHILE - data1 is a pointer to the condition, data2 is a pointer to the body statement; data3,4 are unused
; - STATEMENT_DO - data1 is a pointer to the body statement, data2 is a pointer to the condition; data3,4 are unused
; - STATEMENT_FOR - data1,2,3 are pointers to the first, second, and third expressions inside parentheses, data4 is a pointer to the body statement
; - STATEMENT_GOTO - data1 is a pointer to the name of the label; data2,3,4 are unused
; - STATEMENT_CONTINUE - data1,2,3,4 are unused
; - STATEMENT_BREAK - data1,2,3,4 are unused
; - STATEMENT_RETURN - data1 is a pointer to the expression, or 0 if there is none; data2,3,4 are unused
#define STATEMENT_EXPRESSION 1
#define STATEMENT_LOCAL_DECLARATION 2
#define STATEMENT_LABEL 3
#define STATEMENT_BLOCK 4
#define STATEMENT_IF 5
#define STATEMENT_SWITCH 6
#define STATEMENT_WHILE 7
#define STATEMENT_DO 8
#define STATEMENT_FOR 9
#define STATEMENT_GOTO 0xa
#define STATEMENT_CONTINUE 0xb
#define STATEMENT_BREAK 0xc
#define STATEMENT_RETURN 0xd
:keyword_table
byte SYMBOL_SEMICOLON
byte 59