The Splat Construct

Defining the splat construct.

§1. Definition. For what this does and why it is used, see Textual Inter (in inter).

void SplatInstruction::define_construct(void) {
    inter_construct *IC = InterInstruction::create_construct(SPLAT_IST, I"splat");
    InterInstruction::specify_syntax(IC, I"splat OPTIONALIDENTIFIER TEXT TEXT TEXT");
    InterInstruction::data_extent_always(IC, 6);
    InterInstruction::allow_in_depth_range(IC, 0, INFINITELY_DEEP);
    InterInstruction::permit(IC, OUTSIDE_OF_PACKAGES_ICUP);
    InterInstruction::permit(IC, INSIDE_PLAIN_PACKAGE_ICUP);
    InterInstruction::permit(IC, INSIDE_CODE_PACKAGE_ICUP);
    METHOD_ADD(IC, CONSTRUCT_READ_MTID, SplatInstruction::read);
    METHOD_ADD(IC, CONSTRUCT_TRANSPOSE_MTID, SplatInstruction::transpose);
    METHOD_ADD(IC, CONSTRUCT_VERIFY_MTID, SplatInstruction::verify);
    METHOD_ADD(IC, CONSTRUCT_WRITE_MTID, SplatInstruction::write);
}

§2. Instructions. In bytecode, the frame of a splat instruction is laid out with the compulsory words — see Inter Nodes — followed by:

define MATTER_SPLAT_IFLD         (DATA_IFLD + 0)
define PLM_SPLAT_IFLD            (DATA_IFLD + 1)
define I6ANNOTATION_SPLAT_IFLD   (DATA_IFLD + 2)
define NAMESPACE_SPLAT_IFLD      (DATA_IFLD + 3)
define PROVENANCEFILE_SPLAT_IFLD (DATA_IFLD + 4)
define PROVENANCELINE_SPLAT_IFLD (DATA_IFLD + 5)

inter_error_message *SplatInstruction::new(inter_bookmark *IBM, text_stream *splatter,
    inter_ti plm, text_stream *annotation, text_stream *namespace,
    filename *file, inter_ti line_number, inter_ti level, inter_error_location *eloc) {
    TEMPORARY_TEXT(file_as_text)
    if (file) WRITE_TO(file_as_text, "%f", file);
    inter_tree_node *P = Inode::new_with_6_data_fields(IBM, SPLAT_IST,
        /* MATTER_SPLAT_IFLD: */       InterWarehouse::create_text_at(IBM, splatter),
        /* PLM_SPLAT_IFLD: */          plm,
         I6ANNOTATION_SPLAT_IFLD:
            (Str::len(annotation) > 0)?(InterWarehouse::create_text_at(IBM, annotation)):0,
         NAMESPACE_SPLAT_IFLD:
            (Str::len(namespace) > 0)?(InterWarehouse::create_text_at(IBM, namespace)):0,
         PROVENANCEFILE_SPLAT_IFLD:
            (Str::len(file_as_text) > 0)?(InterWarehouse::create_text_at(IBM, file_as_text)):0,
        /* PROVENANCELINE_SPLAT_IFLD: */ line_number,
        eloc, level);
    DISCARD_TEXT(file_as_text)
    inter_error_message *E = VerifyingInter::instruction(InterBookmark::package(IBM), P);
    if (E) return E;
    NodePlacement::move_to_moving_bookmark(P, IBM);
    return NULL;
}

void SplatInstruction::transpose(inter_construct *IC, inter_tree_node *P, inter_ti *grid,
    inter_ti grid_extent, inter_error_message **E) {
    P->W.instruction[MATTER_SPLAT_IFLD] = grid[P->W.instruction[MATTER_SPLAT_IFLD]];
}

§3. Verification consists only of sanity checks.

void SplatInstruction::verify(inter_construct *IC, inter_tree_node *P,
    inter_package *owner, inter_error_message **E) {
    *E = VerifyingInter::text_field(owner, P, MATTER_SPLAT_IFLD);
    if (*E) return;
    if (SplatInstruction::plm_valid(P->W.instruction[PLM_SPLAT_IFLD]) == FALSE) {
        *E = Inode::error(P, I"plm out of range", NULL);
        return;
    }
    if (P->W.instruction[I6ANNOTATION_SPLAT_IFLD]) {
        *E = VerifyingInter::text_field(owner, P, I6ANNOTATION_SPLAT_IFLD);
        if (*E) return;
    }
}

§4. Creating from textual Inter syntax.

void SplatInstruction::read(inter_construct *IC, inter_bookmark *IBM,
    inter_line_parse *ilp, inter_error_location *eloc, inter_error_message **E) {
    text_stream *plm_text = ilp->mr.exp[0];
    text_stream *annot_text = ilp->mr.exp[1];
    text_stream *namespace_text = ilp->mr.exp[2];
    text_stream *splatter_text = ilp->mr.exp[3];

    inter_ti plm = SplatInstruction::parse_plm(plm_text);
    if (SplatInstruction::plm_valid(plm) == FALSE) {
        *E = InterErrors::plain(I"unknown PLM code before text matter", eloc);
        return;
    }
    TEMPORARY_TEXT(raw)
    TEMPORARY_TEXT(raw_annot)
    TEMPORARY_TEXT(raw_ns)
    *E = TextualInter::parse_literal_text(raw, splatter_text, 0, Str::len(splatter_text), eloc);
    if (*E == NULL) {
        *E = TextualInter::parse_literal_text(raw_annot, annot_text, 0, Str::len(annot_text), eloc);
        if (*E == NULL) {
            *E = TextualInter::parse_literal_text(raw_ns, namespace_text, 0, Str::len(annot_text), eloc);
            if (*E == NULL) {
                filename *F = NULL;
                inter_ti lc = 0;
                if (eloc) {
                    F = eloc->error_tfp->text_file_filename;
                    lc = (inter_ti) eloc->error_tfp->line_count;
                }
                *E = SplatInstruction::new(IBM, raw, plm, raw_annot, raw_ns, F, lc,
                    (inter_ti) ilp->indent_level, eloc);
            }
        }
    }
    DISCARD_TEXT(raw)
    DISCARD_TEXT(raw_annot)
    DISCARD_TEXT(raw_ns)
}

§5. Writing to textual Inter syntax.

void SplatInstruction::write(inter_construct *IC, OUTPUT_STREAM, inter_tree_node *P) {
    WRITE("splat ");
    SplatInstruction::write_plm(OUT, SplatInstruction::plm(P));
    TextualInter::write_text(OUT, SplatInstruction::I6_annotation(P));
    WRITE(" ");
    TextualInter::write_text(OUT, SplatInstruction::namespace(P));
    WRITE(" ");
    TextualInter::write_text(OUT, SplatInstruction::splatter(P));
}

§6. Access function.

inter_ti SplatInstruction::plm(inter_tree_node *P) {
    if (P == NULL) return 0;
    if (Inode::isnt(P, SPLAT_IST)) return 0;
    return P->W.instruction[PLM_SPLAT_IFLD];
}

text_stream *SplatInstruction::splatter(inter_tree_node *P) {
    if (P == NULL) return NULL;
    if (Inode::isnt(P, SPLAT_IST)) return NULL;
    return Inode::ID_to_text(P, P->W.instruction[MATTER_SPLAT_IFLD]);
}

text_stream *SplatInstruction::I6_annotation(inter_tree_node *P) {
    if (P == NULL) return NULL;
    if (Inode::isnt(P, SPLAT_IST)) return NULL;
    return Inode::ID_to_text(P, P->W.instruction[I6ANNOTATION_SPLAT_IFLD]);
}

text_stream *SplatInstruction::namespace(inter_tree_node *P) {
    if (P == NULL) return NULL;
    if (Inode::isnt(P, SPLAT_IST)) return NULL;
    return Inode::ID_to_text(P, P->W.instruction[NAMESPACE_SPLAT_IFLD]);
}

text_provenance SplatInstruction::provenance(inter_tree_node *P) {
    if (P == NULL) return Provenance::nowhere();
    if (Inode::isnt(P, SPLAT_IST)) return Provenance::nowhere();
    return Provenance::at_file_and_line(
        Inode::ID_to_text(P, P->W.instruction[PROVENANCEFILE_SPLAT_IFLD]),
        (int) P->W.instruction[PROVENANCELINE_SPLAT_IFLD]);
}

§7. PLMs. At some point PLM stood for something, but what it was is now forgotten — perhaps "parse linked matter"? — so it is now a nonsense-word pronounced "plum". This is a marker attached to a splat which can indicate which Inform 6-syntax directive the splat contains (if any).

WHITESPACE_PLM should be used only if the splat contains nothing but white space. MYSTERY_PLM should be used if its contents are of an unknown syntax. The other names here are taken from their corresponding I6 directives.

enum IFDEF_PLM from 1
enum IFNDEF_PLM
enum IFNOT_PLM
enum ENDIF_PLM
enum IFTRUE_PLM
enum ORIGSOURCE_PLM
enum CONSTANT_PLM
enum ARRAY_PLM
enum GLOBAL_PLM
enum STUB_PLM
enum ROUTINE_PLM
enum ATTRIBUTE_PLM
enum PROPERTY_PLM
enum VERB_PLM
enum FAKEACTION_PLM
enum OBJECT_PLM
enum DEFAULT_PLM
enum MYSTERY_PLM
enum WHITESPACE_PLM

int SplatInstruction::plm_valid(inter_ti plm) {
    if ((plm == 0) || (plm > WHITESPACE_PLM)) return FALSE;
    return TRUE;
}

§8. Converted to and from text thus. Note that MYSTERY_PLM is used in the case where no PLM is given; so it has the empty textual form, and is not written.

inter_ti SplatInstruction::parse_plm(text_stream *S) {
    if (Str::len(S) == 0)          return MYSTERY_PLM;
    if (Str::eq(S, I"ARRAY"))      return ARRAY_PLM;
    if (Str::eq(S, I"ATTRIBUTE"))  return ATTRIBUTE_PLM;
    if (Str::eq(S, I"CONSTANT"))   return CONSTANT_PLM;
    if (Str::eq(S, I"DEFAULT"))    return DEFAULT_PLM;
    if (Str::eq(S, I"ENDIF"))      return ENDIF_PLM;
    if (Str::eq(S, I"FAKEACTION")) return FAKEACTION_PLM;
    if (Str::eq(S, I"GLOBAL"))     return GLOBAL_PLM;
    if (Str::eq(S, I"IFDEF"))      return IFDEF_PLM;
    if (Str::eq(S, I"IFNDEF"))     return IFNDEF_PLM;
    if (Str::eq(S, I"IFNOT"))      return IFNOT_PLM;
    if (Str::eq(S, I"IFTRUE"))     return IFTRUE_PLM;
    if (Str::eq(S, I"OBJECT"))     return OBJECT_PLM;
    if (Str::eq(S, I"PROPERTY"))   return PROPERTY_PLM;
    if (Str::eq(S, I"ROUTINE"))    return ROUTINE_PLM;
    if (Str::eq(S, I"STUB"))       return STUB_PLM;
    if (Str::eq(S, I"VERB"))       return VERB_PLM;
    if (Str::eq(S, I"WHITESPACE")) return WHITESPACE_PLM;
    return 0;
}

void SplatInstruction::write_plm(OUTPUT_STREAM, inter_ti plm) {
    switch (plm) {
        case ARRAY_PLM:      WRITE("ARRAY "); break;
        case ATTRIBUTE_PLM:  WRITE("ATTRIBUTE "); break;
        case CONSTANT_PLM:   WRITE("CONSTANT "); break;
        case DEFAULT_PLM:    WRITE("DEFAULT "); break;
        case ENDIF_PLM:      WRITE("ENDIF "); break;
        case FAKEACTION_PLM: WRITE("FAKEACTION "); break;
        case GLOBAL_PLM:     WRITE("GLOBAL "); break;
        case IFDEF_PLM:      WRITE("IFDEF "); break;
        case IFNDEF_PLM:     WRITE("IFNDEF "); break;
        case IFNOT_PLM:      WRITE("IFNOT "); break;
        case IFTRUE_PLM:     WRITE("IFTRUE "); break;
        case OBJECT_PLM:     WRITE("OBJECT "); break;
        case PROPERTY_PLM:   WRITE("PROPERTY "); break;
        case ROUTINE_PLM:    WRITE("ROUTINE "); break;
        case STUB_PLM:       WRITE("STUB "); break;
        case VERB_PLM:       WRITE("VERB "); break;
        case WHITESPACE_PLM: WRITE("WHITESPACE "); break;
    }
}